Title of Invention	INJECTABLE COMPOSITIONS FOR THE CONTROLLED DELIVERY OF PHARMACOLOGICALLY ACTIVE COMPOUND
Abstract	The present invention provides compositions and methods for extending the release times and lowering the toxicity of pharmacologically active compounds. The compounds comprise a salt of the pharmacologically active compound with a lipophilic counterion and a pharmaceutically acceptable water soluble solvent combined together to form an injectable composition. The lipophilic counterion may be a saturated or unsaturated C8-C22 fatty acid, and preferably may be a saturated or unsaturated C10-C18 fatty acid. When injected into a mammal, at least a portion of the composition precipitates and releases the active compound over time. Thus, the composition forms a slowly releasing drug depot of the active compound in the mammal. Therefore, the present invention enables one to provide a controlled dose administration of the active compound for a periods of up to 15 days or even longer. Many compounds can be administered according to the present invention including, but not limited to, tilmicosin, oxytetracycline, metoprolol, fluoxetine, roxithromycin, and turbinafine (FIG.)NIL

Title of Invention

INJECTABLE COMPOSITIONS FOR THE CONTROLLED DELIVERY OF PHARMACOLOGICALLY ACTIVE COMPOUND

Abstract

The present invention provides compositions and methods for extending the release times and lowering the toxicity of pharmacologically active compounds. The compounds comprise a salt of the pharmacologically active compound with a lipophilic counterion and a pharmaceutically acceptable water soluble solvent combined together to form an injectable composition. The lipophilic counterion may be a saturated or unsaturated C8-C22 fatty acid, and preferably may be a saturated or unsaturated C10-C18 fatty acid. When injected into a mammal, at least a portion of the composition precipitates and releases the active compound over time. Thus, the composition forms a slowly releasing drug depot of the active compound in the mammal. Therefore, the present invention enables one to provide a controlled dose administration of the active compound for a periods of up to 15 days or even longer. Many compounds can be administered according to the present invention including, but not limited to, tilmicosin, oxytetracycline, metoprolol, fluoxetine, roxithromycin, and turbinafine (FIG.)NIL

Full Text	(0001] The present invention relates to methods and compositions for extending the release times and decreasing the toxicity of pharmacologically active compounds. [0002] The following discussion of the background of the invention is merely provided to aid the reader in understanding the invention and is not admitted to describe or constitute prior art to the present invention. [0003] It is often desirable to extend the release time of an injected drug to increase its duration of action, or to reduce its toxic effects. Formulations that are readily soluble in the body are usually absorbed rapidly and provide a sudden burst of available drug as opposed to a more desirable and gradual release of the pharmacologically active product. A variety of attempts have been made to provide controlled and extended release pharmaceutical compounds, but have not succeeded in overcoming all of the problems associated the technology, such as achieving an extended release time, maximum stability and efficacy, reduced toxicity, maximum reproducibility in preparation, and the elimination of unwanted physical, biochemical, or toxicological effects introduced by undesirable matrix materials. [0004] Oxytetracycline is a widely used and useful antibiotic for treating various infections in mammals. In particular it is used for treating and preventing respiratory infections in domestic animals. There are significant costs associated with repeated administrations through conventional means. [0005J Tilmicosin is a macrolide antibiotic with two tertiary amines. It has a long tissue half-life and is effective against a broad range of bacteria and is used to treat respiratory diseases in cattle. At elevated levels tilmicosin is cardiotoxic and its use in sensitive species such as cats, goats, pigs and horses has been avoided almost entirely due to safety reasons. The commercial product, Micotil® (Eli Lilly & Co., Indianapolis, IN), is a solution of the di-phosphate salt and is described in U.S. Patent No. 5,574,020. This formulation is effective in cattle, but the antibiotic is released rapidly and results in toxicity in many species, including dogs and cats. Summary of the Invention [0006] Application Serial No. 60/343,625, filed October 19,2001 is hereby incorporated by reference in its entirety, including all charts and drawings. [0007] The present invention provides compositions and methods for extending the release times and lowering the toxicity of pharmacologically active compounds. The compounds comprise a salt of the pharmacologically active compound with a iipophilic counterfoil and a pharmaceutically acceptable water soluble solvent combined together to form an injectable composition. The lipophilic counterion may be a saturated or unsaturated C8-C22 fatty acid, and preferably may be a saturated or unsaturated C10-C18 fatty acid. When injected into a mammal, at least a portion of the composition precipitates and releases the active compound over time. Thus, the composition forms a slowly releasing drug depot of the active compound in the mammal. Therefore, the present invention enables one to provide a controlled dose administration of the active compound for a periods of up to 15 days or even longer. In preferred embodiments, the pharmacologically active compound may be tilmicosin, an antibiotic such as oxytetracyclinc or doxycycline, or fluoxetine, roxithromycin, turbinafine, or metoprolol, and the lipophilic counterion may be decanoic acid, lauric acid, oleic acid, linoleic acid, or myristic acid. In preferred embodiments, the pharmaceutically acceptable solvent is N-mcthyl pyrrolidone (NMP). In another embodiment, the pharmaceutically acceptable solvent is propylene glycol (e.g., at about 10%) in glycerol formal, with or without stabilizers. [0008] The present invention also provides novel methods of administering compositions and formulations of the present invention to mammals. The methods provide compositions of active compounds that, if presented in presently available forms, may result in toxicity to the treated mammal. Thus, the formulations and methods of the present invention enable one to administer compounds that previously have not been able to be widely used in particular species due to safety considerations. The methods also enable one to extend the release times of compounds and provide a controlled dose of active compound to the treated patient. The methods of the present invention enable one to administer the pharmacologically active compound to the treated mammal in a pharmaceutically effective amount for 4-15 days, including any specific number of days up to and including 15 days, or even more. The precise time will depend on several variables that may be manipulated to optimize the present invention for a particular pharmacologically active compound or application. Preferably the compound is present in the treated tissue 4-5 days after injection; and more preferably the compound is present in the treated tissue in a pharmaceutically effective amount 6 days, or even 7 days after injection. In other embodiments, it may also be desirable to manipulate variables so as to extend release times even further than 15 days. [0009] In one aspect, the present invention provides compositions for administration of pharmacologically active compounds. The compositions may comprise a salt of the pharmacologically active compound with a lipophilic counterion and a pharmaceutically acceptable water soluble solvent, combined together under conditions to form an injectable composition. The composition may precipitate and release the pharmacologically active compound over time when injected into the mammal. In various embodiments, the composition of the present invention may comprise a wide variety of pharmacologically active compounds such as lilmicosin, oxytetracycline, doxycycline, metoprolol, sulfamethazine, trimethoprim, neomycin, streptomycin, gentamycin, dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole, tetracyclines, sulfonamides, aminoglycosides, or any pharmacologically active compound with appropriate solubility and chemical functionalities. The lipophilic counterion may be a saturated or unsaturated fatty acid of any specific number of carbons between 8 and 22, preferably a C8-C18 fatty acid, and more preferably a C10-C18 fatty acid, such as lauric acid, linoleic acid, decanoic acid, and myristic acid. Other lipophilic counterions may also be used, for example dicarboxylic acids, such as sebacic acid, polymeric acids, such as lipophilic poly-carboxylic acids, and aromatic acids, such as benzoic acid. The pharmaceutically acceptable carrier may be an organic solvent. In preferred embodiments, the solvent may be pyrrolidone, N-methyl pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbid dimethyl ether, ethanol, dimethyl sulfoxide, tetrahydrofurfuryl alcohol, triacetin, or any combination of these, or another solvent found to have similar acceptable properties such as being non-toxic and soluble in water. [0010] In another embodiment the compositions of the invention are a salt of a pharmacologically active compound with a polycarboxylic acid counterion and a pharmaceutically acceptable water soluble solvent, combined together under conditions to form an injectable composition that precipitates when injected into water at room temperature or precipitates in physiological ("in vivo") environments. The composition releases the active compound over time when injected into a mammal. By "polycarboxylic acid" is meant a molecule containing at least two carboxyl groups. In preferred embodiments the polycarboxylic acid is polyaspartic acid, polyacrylic acid, sebacic acid, polysebacic acid, polybenzoic acid, or combinations thereof. By "poly" is meant two or more. [0011] In one embodiment, the pharmacologically active compound may be oxytetracycline, the lipophilic counterion may be lauric acid, and the pharmaceutically acceptable solvent may be propylene glycol, polyethylene glycol, glycerol formal, or an appropriate combination of these. In another embodiment the pharmacologically active compound may be tilmicosin, the lipophilic counterion may be lauric acid, and the pharmaceutically acceptable solvent may be propylene glycol, polyethylene glycol, glycerol formal, or an appropriate combination of these. In still another embodiment, the compositions may precipitate and release the active compound over time when introduced or injected into an aqueous environment. The compositions may also form a drug depot in the mammal when injected, which releases the compound over time. [0012] In another aspect, the present invention provides methods of administering a pharmacologically active compound to a mammal. The methods may comprise preparing a composition of a salt of the pharmacologically active compound with a lipophilic counterion, and a pharmaceutically acceptable water soluble solvent, combined together under conditions to form an injectable formulation, and injecting the composition into the mammal. At least a portion of the composition precipitates and releases the pharmacologically active compound over time when injected into the mammal. [0013] In another aspect, the present invention provides methods of extending the release time of a pharmacologically active compound administered to a mammal. The methods may comprise preparing a formulation of a salt of the pharmacologically active compound with a lipophilic counterion, and a pharmaceutically acceptable water soluble solvent, combined together under conditions to form an injectable formulation, and injecting the composition into the mammal, at least a portion of the composition precipitating and releasing the pharmacologically active compound over time after injection into the mammal, thereby extending the release time of the compound. The invention may therefore provide a controlled dosage of active compound to the treated mammal. [0014] In yet another aspect, the present invention provides methods of manufacturing an injectable formulation for the administration of a pharmacologically active compound to a mammal. The methods may comprise forming a salt of the pharmacologically active compound with a lipophilic counterion, providing water soluble pharmaceutically acceptable solvent, combining the salt and the solvent under conditions to form an injectable formulation, wherein at least a portion of the formulation precipitates and releases the pharmacologically active compound over time when injected into the mammal. [0015] In another aspect the present invention provides compositions for the administration of a pharmacologically active compound to a mammal. The compositions contain a salt of the pharmacologically active compound with a lipophilic counterion and a pharmaceutically acceptable solvent, combined together to form an injectable composition. At least a portion of the pharmaceutically active compound with lipophilic counterion dissolved in the solvent precipitates in vivo and releases the active compound over time when injected into the mammal. [0016] The present invention therefore offers important advantages over formulations previously available. The present invention allows for the controlled release of pharmacologically active compounds to reduce toxicity, particularly in small animals such as dogs and cats. It also offers the advantage of being able to administer compounds to domestic animals in an efficient manner, thereby requiring a smaller investment in time and resources than is available with previous modes of drug administration. The pharmacologically active compound is available in a stable, injectable, formulation that precipitates when injected and slowly releases the active compound over an extended period of time. [0017] The summary of the invention described above is not limiting and other features and advantages of the invention will be apparent from the following detailed with reference to the accompanying drawings description/of the preferred embodiments, as well as from the claims. Brief Description of the Drawings Figure 1 is a graphical illustration showing that oxytetracycline prepared according to the present invention is released into saline at a rate slower than that of the free drug. The solvent is DMSO, and the lipophilic counterion is lauric acid. Figure 2 is a graphical illustration showing that metoprolol prepared according to the present invention is released into saline at a rate slower than that of the free drug. Fatty acid and solvent are lauric acid and N-methylpyrrolidone. Figure 3 is a graphical depiction illustrating that the rate of release of the pharmacologically active compound (tilmicosin) is affected by the chain length of the fatty acid selected. Solvent: N-methyl pyrrolidone; lipophilic counterion: decanoic acid and lauric acid. Figure 4 is a graphical depiction illustrating the solvent effect on in vitro release kinetics in tilmicosin. Lipophilic counterion: di(decanoic) acid; tilmicosin at 100 mg/ml in the formulation. Abbreviations are as follows: PEG = polyethylene glycol, THFA = tetrahydro-furfuryl alcohol, DMA = dimethyl acctamide, ISO-DME = isosorbid dimethyl ether, DMSO = dimethyl sulfoxide, NMP = N-methyl pyrrolidone. Figure 5 is a graphical depiction illustrating that the rate of release of the pharmacologically active compound (tilmicosin) is a function of the concentration of fatty acid salt. Lipophilic counterion: decanoic acid. Figure 6 is a graphical depiction illustrating the in vitro release kinetics of fluoxetine:lauric acid fatty acid salt formulation. Figure 7 is a graphical depiction of the pharmacokinetics of fluoxetine hydrochloride (HC1) and fluoxetine: lauric acid fatty acid salt (FAS) in cats. Figure 8 is a semilog plot of tilmicosin concentration in cat lung tissue over 21 days. Eight male and eight female cats were used and dosed with 10 mg/kg of body weight for all tissue types. Figure 9 is a semilog plot of tilmicosin concentration in cat kidney tissue over 21 days. Eight male and eight female cats were used and dosed with 10 mg/kg of body weight for all tissue types. Figure 10 is a semilog plot of tilmicosin concentration in cat liver tissue over 21 days. Eight male and eight female cats were used and dosed with 10 mg/kg of body weight for all tissue types. Detailed Description of the Invention [0018] The compositions of the present invention may be prepared using salts of pharmacologically active compounds with basic functionalities. These can be made using a variety of lipophilic acids, saturated or unsaturated fatty acids, cholic acids, phosphatidic acids, dicarboxylic acids such as sebacic acid or any acid that, when combined with the pharmacologically active compound, renders the resulting salt insoluble in water, but soluble in a water soluble solvent. By "salt" is meant two compounds that are not covalently linked but are chemically bound through ionic attractions. By "water miscible" is meant that the solvent is capable of mixing in any ratio in water without separation of two phases. By "water soluble" is meant that the solvent has some significant level of solubility in aqueous solutions, e.g., triacetin is considered a water soluble solvent since it is soluble in water at a ratio of about 1:14. By a "lipophilic counterion" is meant an ionic form of a fat soluble molecule. The lipophilic counterion may preferably be a fatty acid, but may also be another fat soluble molecule. The counterion has at least one charge opposite to that of a chemical group on an opposing salt member, thereby causing an ionic attraction between the two molecules. By "injectable formulation" or "injectable composition" is meant a formulation or composition that can be drawin into a syringe and injected subcutaneously, intraperitoneally, or intra-muscularly into a mammal without causing adverse effects due to the presence of solid materials in the composition. Solid materials include, but are not limited to, crystals, a gummy mass, and a gel. By "pharmacologically active compound" is meant a chemical compound that causes a pharmacological effect in the treated mammal. For example, the effect may be to destroy or prevent growth of bacteria or parasites, reduce inflammation, or another pharmaceutical and measurable effect in the treated mammal. [0019] By the verb "precipitate" is meant that the compound forms a precipitate, or solid. A precipitate is an insoluble solid formed in solution at room temperature in vitro or in a physiological (in vivo) environment. The precipitate can take many forms such as, for example, a solid, a crystal, a gummy mass, or a gel. By "pharmaceutically effective amount" is meant an amount that exerts a measurable and medically significant effect on the treated mammal, resulting in progress towards curing or preventing the subject disease, or alleviating or preventing the condition that was the reason for treatment. A "pharmaceutically acceptable solvent" is a liquid that dissolves a salt of the pharmacologically active compound and a lipophilic counterion, and that is suitable for use with humans and/or animals without undue adverse side effects (such as toxicity, irritation, and allergic response) commensurate with a reasonable benefit/risk ratio. [0020] The compositions of the present invention offer several advantages. The compositions are injectable compositions that contain high concentrations of the active compound. In preferred embodiments, the pharmacologically active compound may be loaded into the composition in the range of 10%-60% (w/v). But the person of ordinary skill in the art will realize this range may be varied widely, depending on the solubility or insolubility of the pharmacologically active compound, the lipophilic counterion selected, the solvent selected, the injectability of the final product, and any other relevant needs of the particular application. Active compound may also be loaded as low as 10%, or 5%, or even 1% and still provide a useful effect. Similarly, active compound may be loaded at 70%, or even higher as needs require. No exotic excipients or carriers are required. The compositions are easily filtered, thereby simplifying the manufacturing process. It is believed that the exclusion of water from the formulation should impart greater stability to the formulations, and inhibit the growth of microorganisms. The processes for preparing the compositions, as described herein, are simple, and administration according to the present invention should result in milder reactions at the injection site due to the neutralization of the pharmacologically active compound. [0021] The present invention provides the ability to modulate the release rate and release time of the pharmacologically active compound. The release rate may be modulated by varying the lipophilicity and molecular weight of the counter-ion used to make the salt. For example, lauric acid salts of tilmicosin are usually released more slowly than decanoate salts. In addition, higher concentrations of the salt in the formulation usually yield slower release rates. The decanoate salt of tilmicosin is released more slowly from a 60% tilmicosin-fatty acid salt formulation that from a 30% tilmicosin-fatty acid salt formulation. Similarly, as explained herein, other variables such as selection of lipophilic counterion, solvent selection, salt concentration, and others may be manipulated to lengthen or shorten the release time of the active compound to the desired point. Generally, it may be desirable for salts to be based on the molar ratio of charged groups. But one may also successfully create insoluble salts by utilizing a hemi-salt or by otherwise varying from a 1:1 ratio. The pharmaceutically acceptable solvent may be a water miscible or water soluble solvent, and preferably may be a water miscible solvent. Mixtures of water soluble and/or water miscible solvents may also be utilized. The person of ordinary skill in the art will realize that various water soluble solvents may be mixed to optimize the result for a particular application. For example, a mixture of polyethylene glycol, propylene glycol, and glycerol formal may be mixed in various ratios to provide an optimal solvent. In some embodiments, mixing in approximately even amounts may provide a suitable solvent. [0022] In other embodiments, formulations of the invention containing a salt of the pharmacologically active compound with a lipophilic counterion can be combined with the unsalted form of the active, in order to provide a greater initial dose of active compound. [0023] Without wanting to be bound by any particular theory, injectable compositions may be obtained when a salt is formed of a pharmacologically active agent with a lipophilic counterion, and combined with a parenteral organic solvent. It is believed that when this formulation is injected into a mammal, the solvent may diffuse away from the injection site as aqueous body fluids diffuse towards the site, resulting in the precipitation of the pharmacologically active compound in the treated mammal. The precipitate may take many forms, for example, a solid, crystals, a gummy mass, or a gel. There will thus exist a concentration of the active compound that is released in a pharmaceutically effective amount over a desired period of time. The precipitate may act as a drug depot in the mammal resulting in the release of the compound over a period of time. Release times may be obtained of at least 3 days, at least 4 days, at least 5 days, at least 6 days at least 7 days, or any specific number of days up to and including at least 15 days, or even longer, as desired. By "drug depot" is meant a concentration or precipitation of pharmacologically active compound within the body of the treated mammal that releases a pharmaceutically effective amount of the active compound over time. [0024] It was shown that the fatty acid chain length, the particular combinations of fatty acids, the percent pharmacologically active compound:lipophilic counterion salt in the formulation, and the pharmaceutically acceptable solvent selected all influence the release kinetics of the pharmacologically active compound. Thus, the release kinetics of the pharmacologically active compound may be conveniently and easily managed by manipulating these and other variables. It was also found that the formulations were stable to being sterilized by autoclave. The person of ordinary skill in the art will realize that the present invention may be applied to many pharmacologically active compounds that have an appropriate solubility and chemical functionality. Thus, it is contemplated that the present invention may be applicable to a wide variety of pharmacologically active compounds, such as drugs, medications, nutrients, or other desirable compounds for administration to a mammal. [0025] The person of ordinary skill in the art will realize that some modifications to the methods presented herein may be desirable based on the particular characteristics of the pharmacologically active compound involved. The following non-limiting examples present further applications of the present invention and are provided by way of example only. [0026] Oxytetracycline has one tertiary amine group, and the hydrochloride salt of oxytetracycline is readily soluble in water. We have found that adding one mole of fatty acids to one mole of oxytetracycline creates a salt that has lower solubility in water but is more soluble than the starting oxytetracycline in N-methylpyrrolidone (NMP). When water is added to the NMP formulation, the salt precipitates. [0027] The in vitro rate of release of oxytetracycline may be determined by sealing the formulation in a dialysis bag (Pierce, Rockford, IL), placing it in a reservoir of saline solution, and measuring the amount of drug in the saline as a function of time. The formulation of the present invention was compared with existing oxytetracycline formulations. Fig. 1 shows that the oxytetracycline formulation of the present invention is released into the saline at a rate substantially slower than that of the free drug. [0028] An oxytetracycline composition according to the present invention was prepared by adding 0.464 grams of oxytetracycline and 0.203 grams of lauric acid to 3 ml of NMP. The mixture was stirred for 60 minutes, resulting in a clear solution. 1 ml of this solution was sealed in a dialysis bag, and the bag was suspended in 150 ml of phosphate-buffered saline, pH 7.4. Aliquots were removed at various intervals and oxytetracycline concentration was determined by spectrophotometry. The results in Figure 1 show that oxytetracycline continued to diffuse out of the bag for wore than 120 hours, at which point only about 50% of the oxytetracycline present had been released. Example 2: Metoprolol (0029] Metoprolol is an antihypertensive, antianginal and antiarrhythmic drug, of the following structure: [0030] Its succinate and tartarate salts are available commercially under several trade names. Both these salts as well as the base form of the drug are highly soluble in water. The base form of the metoprolol was prepared from commercially available tartarate salt by standard procedure. When the amine group of metoprolol is neutralized with lauric acid, the resulting salt is poorly soluble in water, but readily soluble in pharmaceutically-acceptablc non-aqueous solvents. A metoprolol composition according to the present invention were prepared by adding 0.3224 grams of metoprolol base and 0.2661 grams of lauric acid to 2.415 ml of NMP. The mixture was stirred for 30 minutes, resulting in a clear solution. One ml of this solution was sealed in a dialysis bag, and the bag was suspended in 150 ml of phosphate-buffered saline, pH 7.4. Aliquots were removed at various intervals and metoprolol concentration was determined by spectrophotometry. The results in Figure 2 show that metoprolol continued to diffuse out of the bag for more than 48 hours while the control solution of metoprolol base (prepared by dissolving 150 mg in 1.124 ml of NMP) is diffused off rapidly. Example 2A: Tilmicosin [0031] Tilmicosin is an antibiotic in the macrolide class with the following structure: [0032] It is effective against a broad range of bacteria, and is used for the treatment of respiratory diseases in cattle. The basic form is moderately soluble in aqueous solutions, while the chloride and phosphate salts are highly soluble. At elevated levels, tilmicosin is cardiotoxic, and therefore is not administered intravenously. For safety reasons, its use has been avoided almost entirely in sensitive species such as cats, goats, pigs, and horses. [0033] When the two amine groups of tilmicosin are neutralized with any of several fatty acids (such as, for example, decanoic C10, lauric C12, myristic C14, palmitic C16, stearic C18, Oleic C10, elaidic C18, linoleic C18, and erucic C22), the resulting salt is poorly soluble in water, but readily soluble in pharmaceutically-acceptable non-aqueous solvents. When the formulation of the salt is sealed in a dialysis cassette and place in saline, the tilmicosin salt precipitates, and tilmicosin is slowly released from the bag. The rate of release is a function of the chain length of the fatty acid (Fig. 3), the solvent (Fig. 4) and the tilmicosin-fatty acid salt concentration (Fig. 5). Example 3 - Tilmicosin salts in vitro [0034] 10 grams (0.0115 moles) of tilmicosin and 0.0253 moles of various carboxylic acids (such as, for example, decanoic, lauric, linoleic, or myristic acids, in individual assays) were taken in a flask and made up to a final volume of 100 ml with N- methyl-pyrrolidone and stirred for 60 minutes to obtain a clear solution. One ml aliquots of these solutions were sealed in dialysis bags, and the bags were suspended in flasks containing 150 ml of phosphate-buffered saline, pH 7.4. The salt was observed to precipitate in the bag within about 1 hour. Aliquots of saline were removed at various intervals and tilmicosin was determined by HPLC. The results with decanoic acid (C- 10) and lauric acid (C-12) salts in Figure 3 show that tilmicosin continued to diffuse out of the bag for more than 120 hours. Longer chain length acids caused a slower release of tilmicosin. Micotil® (Eli Lilly, Indianapolis, IN), a phosphate salt of tilmicosin, is readily soluble and rapidly diffuses from the bag. Example 4 - Tilmicosin-di(decanoic acid) in various solvents [0035] Solutions of tilmicosin di(decanoic acid) salt were prepared in several water-miscible solvents, combining 10 grams (0.0115 moles) of tilmicosin and 0.0253 moles of decanoic acid in various solvents to a final volume of 100 ml. The in vitro release rates were measured using the dialysis method of Example 1. The results in Figure 4 show that the release rate varies with the solvent, but that all of the solvents yield a slower release rate than that observed with the phosphate salt (Micotil (R)) shown in Figure 3. " Example 5 - Tiimicosin release concentration effect [0036] Solutions of tiimicosin di(decanoic acid) salt were prepared by combining 30 grams (0.0345 moles) or 60 grams (0.0690 moles) of tiimicosin with 2 equivalents of decanoic acid in NMP to a final volume of 100 ml. The in vitro release rates were measured using the dialysis method of Example 1, and the data in Figure 5 show that higher starting concentrations result in a slower release rate. Example 6 - Tiimicosin in vivo [0037] Formulations of tiimicosin didecanoate, dilaurate, and dimynstate were formulated at 100 mg/ml in N-methyl pyrrolidone and subcutaneously injected into cats in the back of the neck at a dosage of 45 or 75 mg/kg of body weight. Previous data indicates that a dosage of 25 mg/kg of the phosphate salt of tiimicosin is fatal to cats. The cats showed hypothermia and lethargy after injection, indicative of the bioavailability of the drug. The toxicity was found to be substantially less in formulations with fatty acid chain lengths greater than C10, consistent with the slower release of drug from these formulations. All of the cats survived and were behaving normally 3 days after the injection. The results are summarized in the following Table 1. Table 1: Blood levels of Tiimicosin at Specific Time Intervals (0038) 100 mg/ml of a formulation of a salt of tiimicosin with decanoic acid, lauric acid, or myristic acid in N-methyl pyrrolidone were injected into 9 healthy adult cats at the dosages indicated. The resulting concentrations in blood cells and plasma for each individual cat at 6 hours and 2 days are shown in Table 1. [0039] Tilmicosin salts were also studied in tissue. A tilmicosin:dilauric fatty acid salt in 10% propylene glycol in glycerol formal at 100 mg/ml was administered subcutaneously at 10 mg/kg dose and the biodistribution in cats was determined. [0040] The methods described here were developed for the determination and quantification of tilmicosin in various animal tissues and serum, particularly feline liver, kidney and lung tissue and serum. The person of ordinary skill in the art will realize that many variations of the methods described here are possible without departing from the invention. [0041] The kidney, liver and lung tissue samples were collected 2, 3, 4, 7, 14, and 21 days after injecting the animals with tilmicosin formulation at 10 mg/kg of body weight. The results are presented in Figures 8, 9 & 10. It was found that kidney is the marker tissue in cats while the liver is the marker in cows and pigs. The levels in kidney were consistently higher than in liver with Crnax (kidney: 13.8 meg/gm; Liver: 7.3 mcg/gm) reached around 48 hours in both tissues. The Cmax for lung was found to be 7.5 mcg/gm and was observed around 48 hours after injecting the dose. Detectable levels of tilmicosin persisted in tissues through day 21 of the study. [0042] A drug extraction efficiency of-98% was obtained at a concentration of 1 mcg/gm of tissue. The limit of detection for tilmicosin in various feline tissues was determined to be 0.032 mcg/gm. For feline serum, a drug extraction efficiency of 95% was obtained over a concentration range of 0.15 to 6 mcg/ml after fortification. The limit of detection was determined to be 0.16 mcg/ml with linearity extending from 0.15 to 6 mcg/ml. Preparation of Tissue Samples [0043] Tissue samples were prepared by mincing with scissors or a scalpel on a paper towel. 10 ml of methanol was added to each tube and the samples homogenized separately for 10 to 15 minutes. Samples were sonicated on ice for one minute and centrifuged at 10,000 rpm for 30 minutes at 4 C. The methanol extract was decanted into fresh centrifuge tubes and the tissue samples resuspend in the tubes with 10 mL of methanol and 5.0 mL of 100 mM phosphate. The tubes were vortexed and centrifuged at 10,000 rpm for 30 minutes at 4 C. The extract was decanted into fresh centrifuge tubes and centrifuged at 5000 rpms for 10 minute at 4 C. The methanol extract was added to 70 mL of water in a flask and swirled in the flask to mix. [0044] Each pool of extracts was loaded to a solid phase extraction C18 Sep-Pak Plus® (SPE) cartridge (Waters, Milford, MA) using a vacuum manifold or hydrostatic pump to draw the pools through the cartridges. Once sample were completely loaded, each SPE cartridge was washed with 10 mL of water, and then with 10 mL of 25% acetonitrile / water at a flow rate of less than 5 mL / minute. The SPE cartridges were disconnected from the apparatus and dried completely under high vacuum (26 in. Hg) in a vacuum desiccation jar for 10 minutes. [0045] Analyte was eluted from the SPE cartridges with 5% acetic acid/methanol. Only the first 2.0 mL of eluate was collected. The volumetric flasks were inverted and mixed, and stored overnight at 4 C. [0046] The sample eluates were filtered through a 0.22 urn PVDF filter, and analyzed by HPLC on a SphereClone® 5 um phenyl column (Phenomenex, Torrance, CA). [0047] Fluoxetine is a selective serotonin reuptake inhibitor and is extensively used to treat psychological disorders such as obsessive-compulsive disorder in humans. It is shown that fluoxetine is effective for treating aggressive behavior and separation anxiety in dogs and urine spraying behavior in cats. Fluoxetine is formulated at 100 and 150 mg/ml as a lauric acid salt in 10% propylene glycol in glycerol formal in 1:1 drug to fatty acid ratio. In vitro release kinetics were studied for both formulations at 100 mg/mL concentration using the dialysis technique described in Example 1, and the results presented in Fig 6. Fluoxetine base in 10% propylene glycol in glycerol formal at 100 mg/ml is used as a control in the experiment. While the fluoxetine base formulation is released for about 160 hrs, the 1:1 (drug:LA) lauric acid salt formulation was released for 700 hrs. [0048] The fatty acid salt formulation with 1:1.1 fluoxetine to lauric acid ratio at 150 mg/mL concentration was injected sub cutaneous into cats at 20 and 30 mg/kg. At the same time two cats were dosed at 1 mg/kg/day orally for 28 days. Serum samples were collected through day 42 and analyzed for fluoxetine by HPLC using 35% acetonitrile in phosphate buffer, pH 2.7 on a C18 column. The results suggest that a single sub cutaneous injection of fatty acid salt formulation provide drug concentrations comparable to daily oral dose through 42 days (Fig. 7). [0049] The fluoxetine was also formulated as linoleic acid salt in 10% propylene glycol in glycerol formal, yielding a clear solution. This formulation was also found to precipitate in water. Example 8 - Roxithromycin: [0050] Roxithromycin is an antibiotic in the macrolide class with the following structure: [0051] It is effective against a broad range of bacteria, and is used for the treatment of respiratory diseases in cattle. The amine group of roxithromycin was neutralized with linoleic acid in 10% propylene in glycerol formal, resulting in a clear solution at 200 mg/ml. As in the case of tilmicosin, the salt precipitated when the solution was spiked in water. Example 9 - Turbinafine [0052] Turbinafine is an antifungal and the structure is as shown below: [0053] Turbinafine is a specific inhibitor of squaline epoxidase, ? key enzyme in fungal ergosterol biosynthesis. The amine group of turbinafine was neutralized with linoleic acid in 10% propylene glycol in glycerol formal, resulting in a clear solution at 150 mg/ml. The resulting salt was highly insoluble in water, and precipitated when spiked into water. [0054] While the invention has been described and exemplified in sufficient detail for those skilled in this art to make and use it, various alternatives, modifications, and improvements should be apparent without departing from the spirit and scope of the invention. [0055] One skilled in the art readily appreciates that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Modifications therein and other uses will occur to those skilled in the art. These modifications are encompassed within the spirit of the invention and are defined by the scope of the claims. (0056] It will be readily apparent to a person skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. [0057] All patents and publications mentioned in the specification are indicative of the levels of those of ordinary skill in the art to which the invention pertains. [0058] The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. [0059] In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group. For example, if X is described as selected from the group consisting of bromine, chlorine, and iodine, claims for X being bromine and claims for X being bromine and chlorine are fully described. [0060] Other embodiments are set forth within the following claims. 1. A composition for administration of a pharmacologically active compound to a mammal, comprising: a salt of the pharmacologically active compound with a lipophilic counterion; and a pharmaceutically acceptable solvent; combined together to form an injectable composition mat precipitates when injected in wherein me composition releases the active compound over time when injected into me mammal. 2. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent is a water miscible solvent 3. The composition as claimed in claim 1, wherein the pharmacologically active compound is an antibiotic. 4. The composition as claimed in claim 1, wherein the pharmacologically active compound is tilmicosin, oxytetracycline, doxycycline, fluoxetine, roxithromycin, turbinafine or metoprolol. 5. The composition as claimed in claim 1, wherein the pharmacologically active compound is selected from the group consisting of: trimethoprim, neomycin, streptomycin, gentamycin, dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole, tetracyclines, sulfonamides and aminoglycosides. 6. The composition as claimed in claim 1, wherein the lipophilic counterion is a C10 -C22 saturated or un-saturated fatty acid. 7. The composition as claimed in claim 1, wherein the lipophilic counterion is a C10 -C18 8. The composition as claimed in claim 7, wherein the fatty acid selected from the group consisting of: lauric acid, decanoic acid, myristic acid, oleic acid and linoleic acid. 9. The composition as claimed in claim 1, wherein the lipophilic counterion is a polycarboxylic acid. 10. The composition as claimed in claim 1, wherein the polycarboxylic acid is selected from the group consisting of: sebacic acid, polysebacic acid, polyaspartic acid, polyacrylic acid, and polybenzoic acid. 11. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent is selected from the group consisting of one or a combination of: pyrrolidone, N-methyl pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbide dimethyl ether, ethanol, dimethyl sulfoxide, and tetrahydrofurfuryl alcohol. 12. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent comprises 10% propylene glycol in glycerol formal with or without stabilizers. 13. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent is triacetin. 14. The composition as claimed in claim 1, wherein the pharmacologically active compound is oxytetracycline, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent is selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and glycerol formal. 15. The composition as claimed in claim 1, wherein the pharmacologically active compound is tilmicosin, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent is selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and glycerol formal. 16. A process for preparing a sustained release composition of a pharmacologically active compound to be administered to a mammal comprising: providing a salt of a pharmacologically active compound and a lipophilic counterion; and providing a pharmaceutically acceptable solvent; and combining the salt of a pharmacologically active compound and a lipophilic counterion with the pharmaceutically acceptable solvent to provide the sustained release composition. wherein at least a portion of the sustained release composition precipitates and releases the active compound over time when the composition is injected into mammal. 17. The process as claimed in claim 16, wherein the pharmaceutically acceptable solvent is a water miscible solvent. 18. The process as claimed in claim 16, wherein the pharmaceutically active compound is an antibiotic. 19. The process as claimed in claim 16, wherein the lipophilic counterion is a C10-C18 fatty acid. 20. The process as claimed in claim 18, wherein the antibiotic is tilmicosin, tetracycline, or doxycycline. 21. The process as claimed in claim 18, wherein the antibiotic is selected from the group consisting of: trimethoprim, neomycin, streptomycin, gentamycin, tetracyclines, sulfonamides, and aminoglycosides. 22. The process as claimed in claim 16 wherein the lipophilic counterion is a fatty acid. 23. The process as claimed in claim 22, wherein the fatty acid is a C10-C22 fatty acid. 24. The process as claimed in claim 23, wherein the fatty acid is selected from the group consisting of: lauric acid, decanoic acid, myristic acid, oleic acid and linoleic acid. 25. The process as claimed in claim 16, wherein the lipophilic counterion is sebacic acid. 26. The process as claimed in claim 16, wherein the pharmaceutically acceptable solvent is selected from the group consisting of: pyrrolidone, N-methyl pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbide dimethyl ether, ethanol, dimethyl sulfoxide, and tetrahydrofurfuryl alcohol. 27. The process as claimed in claim 16, wherein the pharmaceutically acceptable solvent is triacetin. 28. The process as claimed in claim 16, wherein the pharmacologically active compound is oxytetracycline, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent is selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and glycerol formal. 29. The method as claimed in claim 16, wherein the pharmacologically active compound is tilmicosin, the lipophilic counterion is decanoic acid, and the pharmaceutically acceptable slovent is selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and glycerol formal. 30. A method of manufacturing an injectable formulation for the administration of a pharmacologically active compound to a mammal comprising, providing a salt of the pharmacologically active compound with a lipophilic counterion; providing a pharmaceutically acceptable solvent; combining the salt and the solvent to form an injectable formulation; wherein at least a portion of the formulation precipitates and releases the active compound over time when injected into the mammal. 31. The method as claimed in claim 30, wherein the pharmaceutically acceptable solvent is a water miscible solvent. 32. The method as claimed in claim 30, wherein the pharmacologically active compound is an antibiotic. 33. The composition as claimed in claim 30, wherein the antibiotic is tilmicosin, oxytetracycline, or doxycycline. 34. The method as claimed in claim 30, wherein the lipophilic counterion is a C10 - C18 fatty acid. 35. The method as claimed in claim 34, wherein the fatty acid is selected from the group consisting of : lauric acid, decanoic acid, and myristic acid. 36. The method as claimed in claim 30, wherein the lipophilic counterion is sebacic acid. 37. The method as claimed in claim 30, wherein the pharmaceutically acceptable solvent is selected from the group consisting of: pyrrolidone, N-methyl pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbide dimethyl ether, ethanol, dimethyl sulfoxide, and tetrahydrofurfuryl alcohol. 38. The method as claimed in claim 30, wherein the pharmaceutically acceptable solvent is triacetin. 39. The method as claimed in claim 30, wherein the pharmacologically active compound is oxytetracycline, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent is selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and glycerol formal. 40. The method as claimed in claim 30, wherein the pharmacologically active compound is tilmicosin, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent is selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and glycerol formal. 41. A composition for administration of a pharmacologically active compound to a mammal, comprising: a salt of the pharmacologically active compound with a lipophilic counterion; and a pharmaceutically acceptable solvent combined together to form an injectable composition; and wherein at least a portion of the composition precipitates and releases the active compound over time when injected into an aqueous environment. 42. The composition as claimed in claim 41, wherein the pharmaceutically acceptable solvent is water miscible. 43. The composition as claimed in claim 41, wherein the antibiotic is tilmicosin, oxytetracycline, or doxycycline. 44. The composition as claimed in claim 41, wherein the pharmacologically active compound is selected from the group consisting of: trimethoprim, neomycin, streptomycin, gentamycin, dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole, tetracyclines, sulfonamides and aminoglycosides. 45. The composition as claimed in claim 41, wherein the lipophilic counterion is a C10 - C18 fatty acid. 46. The composition as claimed in claim 45, wherein the fatty acid selected from the group consisting of: lauric acid, decanoic acid, and myristic acid. 47 The composition as claimed in claim 41, wherein the lipophilic counterion is sebacic acid. 48. The composition as claimed in claim 41, wherein the pharmaceutically acceptable solvent is selected from the group consisting of one or a combination of: pyrrolidone, N-methyl pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbide dimethyl ether, ethanol, dimethyl sulfoxide, and tetrahydrofurfuryl alcohol. 49. The composition as claimed in claim 41, wherein the pharmaceutically acceptable solvent is triacetin. 50. A composition for administration of a pharmacologically active compound to a mammal, comprising: a salt of the pharmacologically active compound with a lipophilic counterion; and a pharmaceutically acceptable solvent; combined together to form an injectable composition; and wherein at least a portion of the pharmaceutically active compound and lipophilic counterion dissolves in the solvent and precipitates in vivo. 51. A composition for administration of a pharmacologically active compound to a mammal, comprising: a salt of the pharmacologically active compound with a polycarboxylic acid counterion; and a pharmaceutically acceptable solvent; combined together to form an injectable composition that precipitates when injected into) water and wherein the composition releases the active compound over time when injected into the mammal. 52. The composition as claimed in claim 51, wherein the polycarboxylic acid is selected from the group consisting of: polyaspartic acid, polyacrylic acid, sebacic acid, polysebacic acid, and polybenzoic acid. 53. The composition as claimed in claim 51, wherein the pharmaceutically acceptable solvent is a water miscible solvent. 54. The composition as claimed in claim 51, wherein the pharmacologically active compound is an antibiotic. 55. The composition as claimed in claim 51, wherein the pharmacologically active compound is tilmicosin, oxytetracycline, doxycycline, fluoxetine, roxithromycin, terbinafine or metoprolol. 56. The composing as claimed in claim 51, wherein the pharmacologically active compound is selected from the group consisting of: trimethoprim, neomycin, streptomycin, gentamycin, dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole, tetracyclines, sulfonamides, and aminoglycosides. The present invention provides compositions and methods for extending the release times and lowering the toxicity of pharmacologically active compounds. The compounds comprise a salt of the pharmacologically active compound with a lipophilic counterion and a pharmaceutically acceptable water soluble solvent combined together to form an injectable composition. The lipophilic counterion may be a saturated or unsaturated C8 - C22 fatty acid, and preferably may be a saturated or unsaturated C10 - C18 fatty acid. When injected into a mammal, at least a portion of the composition precipitates and releases the active compound over time. Thus, the composition forms a slowly releasing drug depot of the active compound in the mammal. Therefore, the present invention enables one to provide a controlled dose administration of the active compound for a periods of up to 15 days or even longer. Many compounds can be administered according to the present invention including, but not limited to, tilmicosin, oxytetracycline, metoprolol, fluoxetine, roxithromycin, and turbinafine.

Full Text

(0001] The present invention relates to methods and compositions for extending
the release times and decreasing the toxicity of pharmacologically active compounds.
[0002] The following discussion of the background of the invention is merely
provided to aid the reader in understanding the invention and is not admitted to describe
or constitute prior art to the present invention.
[0003] It is often desirable to extend the release time of an injected drug to
increase its duration of action, or to reduce its toxic effects. Formulations that are readily
soluble in the body are usually absorbed rapidly and provide a sudden burst of available
drug as opposed to a more desirable and gradual release of the pharmacologically active
product. A variety of attempts have been made to provide controlled and extended
release pharmaceutical compounds, but have not succeeded in overcoming all of the
problems associated the technology, such as achieving an extended release time,
maximum stability and efficacy, reduced toxicity, maximum reproducibility in
preparation, and the elimination of unwanted physical, biochemical, or toxicological
effects introduced by undesirable matrix materials.
[0004] Oxytetracycline is a widely used and useful antibiotic for treating various
infections in mammals. In particular it is used for treating and preventing respiratory
infections in domestic animals. There are significant costs associated with repeated
administrations through conventional means.
[0005J Tilmicosin is a macrolide antibiotic with two tertiary amines. It has a
long tissue half-life and is effective against a broad range of bacteria and is used to treat
respiratory diseases in cattle. At elevated levels tilmicosin is cardiotoxic and its use in
sensitive species such as cats, goats, pigs and horses has been avoided almost entirely
due to safety reasons. The commercial product, Micotil® (Eli Lilly & Co., Indianapolis,
IN), is a solution of the di-phosphate salt and is described in U.S. Patent No. 5,574,020.
This formulation is effective in cattle, but the antibiotic is released rapidly and results in
toxicity in many species, including dogs and cats.
Summary of the Invention
[0006] Application Serial No. 60/343,625, filed October 19,2001 is hereby
incorporated by reference in its entirety, including all charts and drawings.
[0007] The present invention provides compositions and methods for extending
the release times and lowering the toxicity of pharmacologically active compounds. The
compounds comprise a salt of the pharmacologically active compound with a iipophilic
counterfoil and a pharmaceutically acceptable water soluble solvent combined together to
form an injectable composition. The lipophilic counterion may be a saturated or
unsaturated C8-C22 fatty acid, and preferably may be a saturated or unsaturated C10-C18
fatty acid. When injected into a mammal, at least a portion of the composition
precipitates and releases the active compound over time. Thus, the composition forms a
slowly releasing drug depot of the active compound in the mammal. Therefore, the
present invention enables one to provide a controlled dose administration of the active
compound for a periods of up to 15 days or even longer. In preferred embodiments, the
pharmacologically active compound may be tilmicosin, an antibiotic such as
oxytetracyclinc or doxycycline, or fluoxetine, roxithromycin, turbinafine, or metoprolol,
and the lipophilic counterion may be decanoic acid, lauric acid, oleic acid, linoleic acid,
or myristic acid. In preferred embodiments, the pharmaceutically acceptable solvent is
N-mcthyl pyrrolidone (NMP). In another embodiment, the pharmaceutically acceptable
solvent is propylene glycol (e.g., at about 10%) in glycerol formal, with or without
stabilizers.
[0008] The present invention also provides novel methods of administering
compositions and formulations of the present invention to mammals. The methods
provide compositions of active compounds that, if presented in presently available forms,
may result in toxicity to the treated mammal. Thus, the formulations and methods of the
present invention enable one to administer compounds that previously have not been able
to be widely used in particular species due to safety considerations. The methods also
enable one to extend the release times of compounds and provide a controlled dose of
active compound to the treated patient. The methods of the present invention enable one
to administer the pharmacologically active compound to the treated mammal in a
pharmaceutically effective amount for 4-15 days, including any specific number of days
up to and including 15 days, or even more. The precise time will depend on several
variables that may be manipulated to optimize the present invention for a particular
pharmacologically active compound or application. Preferably the compound is present
in the treated tissue 4-5 days after injection; and more preferably the compound is
present in the treated tissue in a pharmaceutically effective amount 6 days, or even 7
days after injection. In other embodiments, it may also be desirable to manipulate
variables so as to extend release times even further than 15 days.
[0009] In one aspect, the present invention provides compositions for
administration of pharmacologically active compounds. The compositions may
comprise a salt of the pharmacologically active compound with a lipophilic counterion
and a pharmaceutically acceptable water soluble solvent, combined together under
conditions to form an injectable composition. The composition may precipitate and
release the pharmacologically active compound over time when injected into the
mammal. In various embodiments, the composition of the present invention may
comprise a wide variety of pharmacologically active compounds such as lilmicosin,
oxytetracycline, doxycycline, metoprolol, sulfamethazine, trimethoprim, neomycin,
streptomycin, gentamycin, dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine,
itraconazole, tetracyclines, sulfonamides, aminoglycosides, or any pharmacologically
active compound with appropriate solubility and chemical functionalities. The lipophilic
counterion may be a saturated or unsaturated fatty acid of any specific number of carbons
between 8 and 22, preferably a C8-C18 fatty acid, and more preferably a C10-C18 fatty
acid, such as lauric acid, linoleic acid, decanoic acid, and myristic acid. Other lipophilic
counterions may also be used, for example dicarboxylic acids, such as sebacic acid,
polymeric acids, such as lipophilic poly-carboxylic acids, and aromatic acids, such as
benzoic acid. The pharmaceutically acceptable carrier may be an organic solvent. In
preferred embodiments, the solvent may be pyrrolidone, N-methyl pyrrolidone,
polyethylene glycol, propylene glycol, glycerol formal, isosorbid dimethyl ether, ethanol,
dimethyl sulfoxide, tetrahydrofurfuryl alcohol, triacetin, or any combination of these, or
another solvent found to have similar acceptable properties such as being non-toxic and
soluble in water.
[0010] In another embodiment the compositions of the invention are a salt of a
pharmacologically active compound with a polycarboxylic acid counterion and a
pharmaceutically acceptable water soluble solvent, combined together under conditions
to form an injectable composition that precipitates when injected into water at room
temperature or precipitates in physiological ("in vivo") environments. The composition
releases the active compound over time when injected into a mammal. By
"polycarboxylic acid" is meant a molecule containing at least two carboxyl groups. In
preferred embodiments the polycarboxylic acid is polyaspartic acid, polyacrylic acid,
sebacic acid, polysebacic acid, polybenzoic acid, or combinations thereof. By "poly" is
meant two or more.
[0011] In one embodiment, the pharmacologically active compound may be
oxytetracycline, the lipophilic counterion may be lauric acid, and the pharmaceutically
acceptable solvent may be propylene glycol, polyethylene glycol, glycerol formal, or an
appropriate combination of these. In another embodiment the pharmacologically active
compound may be tilmicosin, the lipophilic counterion may be lauric acid, and the
pharmaceutically acceptable solvent may be propylene glycol, polyethylene glycol,
glycerol formal, or an appropriate combination of these. In still another embodiment, the
compositions may precipitate and release the active compound over time when
introduced or injected into an aqueous environment. The compositions may also form a
drug depot in the mammal when injected, which releases the compound over time.
[0012] In another aspect, the present invention provides methods of
administering a pharmacologically active compound to a mammal. The methods may
comprise preparing a composition of a salt of the pharmacologically active compound
with a lipophilic counterion, and a pharmaceutically acceptable water soluble solvent,
combined together under conditions to form an injectable formulation, and injecting the
composition into the mammal. At least a portion of the composition precipitates and
releases the pharmacologically active compound over time when injected into the
mammal.
[0013] In another aspect, the present invention provides methods of extending the
release time of a pharmacologically active compound administered to a mammal. The
methods may comprise preparing a formulation of a salt of the pharmacologically active
compound with a lipophilic counterion, and a pharmaceutically acceptable water soluble
solvent, combined together under conditions to form an injectable formulation, and
injecting the composition into the mammal, at least a portion of the composition
precipitating and releasing the pharmacologically active compound over time after
injection into the mammal, thereby extending the release time of the compound. The
invention may therefore provide a controlled dosage of active compound to the treated
mammal.
[0014] In yet another aspect, the present invention provides methods of
manufacturing an injectable formulation for the administration of a pharmacologically
active compound to a mammal. The methods may comprise forming a salt of the
pharmacologically active compound with a lipophilic counterion, providing water
soluble pharmaceutically acceptable solvent, combining the salt and the solvent under
conditions to form an injectable formulation, wherein at least a portion of the
formulation precipitates and releases the pharmacologically active compound over time
when injected into the mammal.
[0015] In another aspect the present invention provides compositions for the
administration of a pharmacologically active compound to a mammal. The compositions
contain a salt of the pharmacologically active compound with a lipophilic counterion and
a pharmaceutically acceptable solvent, combined together to form an injectable
composition. At least a portion of the pharmaceutically active compound with lipophilic
counterion dissolved in the solvent precipitates in vivo and releases the active compound
over time when injected into the mammal.
[0016] The present invention therefore offers important advantages over
formulations previously available. The present invention allows for the controlled
release of pharmacologically active compounds to reduce toxicity, particularly in small
animals such as dogs and cats. It also offers the advantage of being able to administer
compounds to domestic animals in an efficient manner, thereby requiring a smaller
investment in time and resources than is available with previous modes of drug
administration. The pharmacologically active compound is available in a stable,
injectable, formulation that precipitates when injected and slowly releases the active
compound over an extended period of time.
[0017] The summary of the invention described above is not limiting and other
features and advantages of the invention will be apparent from the following detailed
with reference to the accompanying drawings
description/of the preferred embodiments, as well as from the claims.
Brief Description of the Drawings
Figure 1 is a graphical illustration showing that oxytetracycline prepared
according to the present invention is released into saline at a rate slower than that of the
free drug. The solvent is DMSO, and the lipophilic counterion is lauric acid.
Figure 2 is a graphical illustration showing that metoprolol prepared according to
the present invention is released into saline at a rate slower than that of the free drug.
Fatty acid and solvent are lauric acid and N-methylpyrrolidone.
Figure 3 is a graphical depiction illustrating that the rate of release of the
pharmacologically active compound (tilmicosin) is affected by the chain length of the
fatty acid selected. Solvent: N-methyl pyrrolidone; lipophilic counterion: decanoic acid
and lauric acid.
Figure 4 is a graphical depiction illustrating the solvent effect on in vitro release
kinetics in tilmicosin. Lipophilic counterion: di(decanoic) acid; tilmicosin at 100 mg/ml
in the formulation. Abbreviations are as follows: PEG = polyethylene glycol, THFA =
tetrahydro-furfuryl alcohol, DMA = dimethyl acctamide, ISO-DME = isosorbid dimethyl
ether, DMSO = dimethyl sulfoxide, NMP = N-methyl pyrrolidone.
Figure 5 is a graphical depiction illustrating that the rate of release of the
pharmacologically active compound (tilmicosin) is a function of the concentration of
fatty acid salt. Lipophilic counterion: decanoic acid.
Figure 6 is a graphical depiction illustrating the in vitro release kinetics of
fluoxetine:lauric acid fatty acid salt formulation.
Figure 7 is a graphical depiction of the pharmacokinetics of fluoxetine
hydrochloride (HC1) and fluoxetine: lauric acid fatty acid salt (FAS) in cats.
Figure 8 is a semilog plot of tilmicosin concentration in cat lung tissue over 21
days. Eight male and eight female cats were used and dosed with 10 mg/kg of body
weight for all tissue types.
Figure 9 is a semilog plot of tilmicosin concentration in cat kidney tissue over 21
days. Eight male and eight female cats were used and dosed with 10 mg/kg of body
weight for all tissue types.
Figure 10 is a semilog plot of tilmicosin concentration in cat liver tissue over 21
days. Eight male and eight female cats were used and dosed with 10 mg/kg of body
weight for all tissue types.
Detailed Description of the Invention
[0018] The compositions of the present invention may be prepared using salts of
pharmacologically active compounds with basic functionalities. These can be made
using a variety of lipophilic acids, saturated or unsaturated fatty acids, cholic acids,
phosphatidic acids, dicarboxylic acids such as sebacic acid or any acid that, when
combined with the pharmacologically active compound, renders the resulting salt
insoluble in water, but soluble in a water soluble solvent. By "salt" is meant two
compounds that are not covalently linked but are chemically bound through ionic
attractions. By "water miscible" is meant that the solvent is capable of mixing in any
ratio in water without separation of two phases. By "water soluble" is meant that the
solvent has some significant level of solubility in aqueous solutions, e.g., triacetin is
considered a water soluble solvent since it is soluble in water at a ratio of about 1:14. By
a "lipophilic counterion" is meant an ionic form of a fat soluble molecule. The lipophilic
counterion may preferably be a fatty acid, but may also be another fat soluble molecule.
The counterion has at least one charge opposite to that of a chemical group on an
opposing salt member, thereby causing an ionic attraction between the two molecules.
By "injectable formulation" or "injectable composition" is meant a formulation or
composition that can be drawin into a syringe and injected subcutaneously,
intraperitoneally, or intra-muscularly into a mammal without causing adverse effects due
to the presence of solid materials in the composition. Solid materials include, but are not
limited to, crystals, a gummy mass, and a gel. By "pharmacologically active compound"
is meant a chemical compound that causes a pharmacological effect in the treated
mammal. For example, the effect may be to destroy or prevent growth of bacteria or
parasites, reduce inflammation, or another pharmaceutical and measurable effect in the
treated mammal.
[0019] By the verb "precipitate" is meant that the compound forms a precipitate,
or solid. A precipitate is an insoluble solid formed in solution at room temperature in
vitro or in a physiological (in vivo) environment. The precipitate can take many forms
such as, for example, a solid, a crystal, a gummy mass, or a gel. By "pharmaceutically
effective amount" is meant an amount that exerts a measurable and medically significant
effect on the treated mammal, resulting in progress towards curing or preventing the
subject disease, or alleviating or preventing the condition that was the reason for
treatment. A "pharmaceutically acceptable solvent" is a liquid that dissolves a salt of the
pharmacologically active compound and a lipophilic counterion, and that is suitable for
use with humans and/or animals without undue adverse side effects (such as toxicity,
irritation, and allergic response) commensurate with a reasonable benefit/risk ratio.
[0020] The compositions of the present invention offer several advantages. The
compositions are injectable compositions that contain high concentrations of the active
compound. In preferred embodiments, the pharmacologically active compound may be
loaded into the composition in the range of 10%-60% (w/v). But the person of ordinary
skill in the art will realize this range may be varied widely, depending on the solubility or
insolubility of the pharmacologically active compound, the lipophilic counterion
selected, the solvent selected, the injectability of the final product, and any other relevant
needs of the particular application. Active compound may also be loaded as low as 10%,
or 5%, or even 1% and still provide a useful effect. Similarly, active compound may be
loaded at 70%, or even higher as needs require. No exotic excipients or carriers are
required. The compositions are easily filtered, thereby simplifying the manufacturing
process. It is believed that the exclusion of water from the formulation should impart
greater stability to the formulations, and inhibit the growth of microorganisms. The
processes for preparing the compositions, as described herein, are simple, and
administration according to the present invention should result in milder reactions at the
injection site due to the neutralization of the pharmacologically active compound.
[0021] The present invention provides the ability to modulate the release rate and
release time of the pharmacologically active compound. The release rate may be
modulated by varying the lipophilicity and molecular weight of the counter-ion used to
make the salt. For example, lauric acid salts of tilmicosin are usually released more
slowly than decanoate salts. In addition, higher concentrations of the salt in the
formulation usually yield slower release rates. The decanoate salt of tilmicosin is
released more slowly from a 60% tilmicosin-fatty acid salt formulation that from a 30%
tilmicosin-fatty acid salt formulation. Similarly, as explained herein, other variables
such as selection of lipophilic counterion, solvent selection, salt concentration, and
others may be manipulated to lengthen or shorten the release time of the active
compound to the desired point. Generally, it may be desirable for salts to be based on
the molar ratio of charged groups. But one may also successfully create insoluble salts
by utilizing a hemi-salt or by otherwise varying from a 1:1 ratio. The pharmaceutically
acceptable solvent may be a water miscible or water soluble solvent, and preferably may
be a water miscible solvent. Mixtures of water soluble and/or water miscible solvents
may also be utilized. The person of ordinary skill in the art will realize that various
water soluble solvents may be mixed to optimize the result for a particular application.
For example, a mixture of polyethylene glycol, propylene glycol, and glycerol formal
may be mixed in various ratios to provide an optimal solvent. In some embodiments,
mixing in approximately even amounts may provide a suitable solvent.
[0022] In other embodiments, formulations of the invention containing a salt of
the pharmacologically active compound with a lipophilic counterion can be combined
with the unsalted form of the active, in order to provide a greater initial dose of active
compound.
[0023] Without wanting to be bound by any particular theory, injectable
compositions may be obtained when a salt is formed of a pharmacologically active agent
with a lipophilic counterion, and combined with a parenteral organic solvent. It is
believed that when this formulation is injected into a mammal, the solvent may diffuse
away from the injection site as aqueous body fluids diffuse towards the site, resulting in
the precipitation of the pharmacologically active compound in the treated mammal. The
precipitate may take many forms, for example, a solid, crystals, a gummy mass, or a gel.
There will thus exist a concentration of the active compound that is released in a
pharmaceutically effective amount over a desired period of time. The precipitate may act
as a drug depot in the mammal resulting in the release of the compound over a period of
time. Release times may be obtained of at least 3 days, at least 4 days, at least 5 days, at
least 6 days at least 7 days, or any specific number of days up to and including at least 15
days, or even longer, as desired. By "drug depot" is meant a concentration or
precipitation of pharmacologically active compound within the body of the treated
mammal that releases a pharmaceutically effective amount of the active compound over
time.
[0024] It was shown that the fatty acid chain length, the particular combinations
of fatty acids, the percent pharmacologically active compound:lipophilic counterion salt
in the formulation, and the pharmaceutically acceptable solvent selected all influence the
release kinetics of the pharmacologically active compound. Thus, the release kinetics of
the pharmacologically active compound may be conveniently and easily managed by
manipulating these and other variables. It was also found that the formulations were
stable to being sterilized by autoclave. The person of ordinary skill in the art will realize
that the present invention may be applied to many pharmacologically active compounds
that have an appropriate solubility and chemical functionality. Thus, it is contemplated
that the present invention may be applicable to a wide variety of pharmacologically
active compounds, such as drugs, medications, nutrients, or other desirable compounds
for administration to a mammal.
[0025] The person of ordinary skill in the art will realize that some modifications
to the methods presented herein may be desirable based on the particular characteristics
of the pharmacologically active compound involved. The following non-limiting
examples present further applications of the present invention and are provided by way
of example only.
[0026] Oxytetracycline has one tertiary amine group, and the hydrochloride salt
of oxytetracycline is readily soluble in water. We have found that adding one mole of
fatty acids to one mole of oxytetracycline creates a salt that has lower solubility in water
but is more soluble than the starting oxytetracycline in N-methylpyrrolidone (NMP).
When water is added to the NMP formulation, the salt precipitates.
[0027] The in vitro rate of release of oxytetracycline may be determined by
sealing the formulation in a dialysis bag (Pierce, Rockford, IL), placing it in a reservoir
of saline solution, and measuring the amount of drug in the saline as a function of time.
The formulation of the present invention was compared with existing oxytetracycline
formulations. Fig. 1 shows that the oxytetracycline formulation of the present invention
is released into the saline at a rate substantially slower than that of the free drug.
[0028] An oxytetracycline composition according to the present invention was
prepared by adding 0.464 grams of oxytetracycline and 0.203 grams of lauric acid to 3
ml of NMP. The mixture was stirred for 60 minutes, resulting in a clear solution. 1 ml
of this solution was sealed in a dialysis bag, and the bag was suspended in 150 ml of
phosphate-buffered saline, pH 7.4. Aliquots were removed at various intervals and
oxytetracycline concentration was determined by spectrophotometry. The results in
Figure 1 show that oxytetracycline continued to diffuse out of the bag for wore than 120
hours, at which point only about 50% of the oxytetracycline present had been released.
Example 2: Metoprolol
(0029] Metoprolol is an antihypertensive, antianginal and antiarrhythmic drug, of
the following structure:
[0030] Its succinate and tartarate salts are available commercially under several
trade names. Both these salts as well as the base form of the drug are highly soluble in
water. The base form of the metoprolol was prepared from commercially available
tartarate salt by standard procedure. When the amine group of metoprolol is neutralized
with lauric acid, the resulting salt is poorly soluble in water, but readily soluble in
pharmaceutically-acceptablc non-aqueous solvents. A metoprolol composition
according to the present invention were prepared by adding 0.3224 grams of metoprolol
base and 0.2661 grams of lauric acid to 2.415 ml of NMP. The mixture was stirred for
30 minutes, resulting in a clear solution. One ml of this solution was sealed in a dialysis
bag, and the bag was suspended in 150 ml of phosphate-buffered saline, pH 7.4.
Aliquots were removed at various intervals and metoprolol concentration was
determined by spectrophotometry. The results in Figure 2 show that metoprolol
continued to diffuse out of the bag for more than 48 hours while the control solution of
metoprolol base (prepared by dissolving 150 mg in 1.124 ml of NMP) is diffused off
rapidly.
Example 2A: Tilmicosin
[0031] Tilmicosin is an antibiotic in the macrolide class with the following
structure:
[0032] It is effective against a broad range of bacteria, and is used for the
treatment of respiratory diseases in cattle. The basic form is moderately soluble in
aqueous solutions, while the chloride and phosphate salts are highly soluble. At elevated
levels, tilmicosin is cardiotoxic, and therefore is not administered intravenously. For
safety reasons, its use has been avoided almost entirely in sensitive species such as cats,
goats, pigs, and horses.
[0033] When the two amine groups of tilmicosin are neutralized with any of
several fatty acids (such as, for example, decanoic C10, lauric C12, myristic C14, palmitic
C16, stearic C18, Oleic C10, elaidic C18, linoleic C18, and erucic C22), the resulting salt is
poorly soluble in water, but readily soluble in pharmaceutically-acceptable non-aqueous
solvents. When the formulation of the salt is sealed in a dialysis cassette and place in
saline, the tilmicosin salt precipitates, and tilmicosin is slowly released from the bag.
The rate of release is a function of the chain length of the fatty acid (Fig. 3), the solvent
(Fig. 4) and the tilmicosin-fatty acid salt concentration (Fig. 5).
Example 3 - Tilmicosin salts in vitro
[0034] 10 grams (0.0115 moles) of tilmicosin and 0.0253 moles of various
carboxylic acids (such as, for example, decanoic, lauric, linoleic, or myristic acids, in
individual assays) were taken in a flask and made up to a final volume of 100 ml with N-
methyl-pyrrolidone and stirred for 60 minutes to obtain a clear solution. One ml aliquots
of these solutions were sealed in dialysis bags, and the bags were suspended in flasks
containing 150 ml of phosphate-buffered saline, pH 7.4. The salt was observed to
precipitate in the bag within about 1 hour. Aliquots of saline were removed at various
intervals and tilmicosin was determined by HPLC. The results with decanoic acid (C-
10) and lauric acid (C-12) salts in Figure 3 show that tilmicosin continued to diffuse out
of the bag for more than 120 hours. Longer chain length acids caused a slower release of
tilmicosin. Micotil® (Eli Lilly, Indianapolis, IN), a phosphate salt of tilmicosin, is
readily soluble and rapidly diffuses from the bag.
Example 4 - Tilmicosin-di(decanoic acid) in various solvents
[0035] Solutions of tilmicosin di(decanoic acid) salt were prepared in several
water-miscible solvents, combining 10 grams (0.0115 moles) of tilmicosin and 0.0253
moles of decanoic acid in various solvents to a final volume of 100 ml. The in vitro
release rates were measured using the dialysis method of Example 1. The results in
Figure 4 show that the release rate varies with the solvent, but that all of the solvents
yield a slower release rate than that observed with the phosphate salt (Micotil (R)) shown
in Figure 3.
" Example 5 - Tiimicosin release concentration effect
[0036] Solutions of tiimicosin di(decanoic acid) salt were prepared by combining
30 grams (0.0345 moles) or 60 grams (0.0690 moles) of tiimicosin with 2 equivalents of
decanoic acid in NMP to a final volume of 100 ml. The in vitro release rates were
measured using the dialysis method of Example 1, and the data in Figure 5 show that
higher starting concentrations result in a slower release rate.
Example 6 - Tiimicosin in vivo
[0037] Formulations of tiimicosin didecanoate, dilaurate, and dimynstate were
formulated at 100 mg/ml in N-methyl pyrrolidone and subcutaneously injected into cats
in the back of the neck at a dosage of 45 or 75 mg/kg of body weight. Previous data
indicates that a dosage of 25 mg/kg of the phosphate salt of tiimicosin is fatal to cats.
The cats showed hypothermia and lethargy after injection, indicative of the
bioavailability of the drug. The toxicity was found to be substantially less in
formulations with fatty acid chain lengths greater than C10, consistent with the slower
release of drug from these formulations. All of the cats survived and were behaving
normally 3 days after the injection. The results are summarized in the following Table 1.
Table 1: Blood levels of Tiimicosin at Specific Time Intervals
(0038) 100 mg/ml of a formulation of a salt of tiimicosin with decanoic acid,
lauric acid, or myristic acid in N-methyl pyrrolidone were injected into 9 healthy adult
cats at the dosages indicated. The resulting concentrations in blood cells and plasma for
each individual cat at 6 hours and 2 days are shown in Table 1.
[0039] Tilmicosin salts were also studied in tissue. A tilmicosin:dilauric fatty
acid salt in 10% propylene glycol in glycerol formal at 100 mg/ml was administered
subcutaneously at 10 mg/kg dose and the biodistribution in cats was determined.
[0040] The methods described here were developed for the determination and
quantification of tilmicosin in various animal tissues and serum, particularly feline liver,
kidney and lung tissue and serum. The person of ordinary skill in the art will realize that
many variations of the methods described here are possible without departing from the
invention.
[0041] The kidney, liver and lung tissue samples were collected 2, 3, 4, 7, 14,
and 21 days after injecting the animals with tilmicosin formulation at 10 mg/kg of body
weight. The results are presented in Figures 8, 9 & 10. It was found that kidney is the
marker tissue in cats while the liver is the marker in cows and pigs. The levels in kidney
were consistently higher than in liver with Crnax (kidney: 13.8 meg/gm; Liver: 7.3
mcg/gm) reached around 48 hours in both tissues. The Cmax for lung was found to be
7.5 mcg/gm and was observed around 48 hours after injecting the dose. Detectable
levels of tilmicosin persisted in tissues through day 21 of the study.
[0042] A drug extraction efficiency of-98% was obtained at a concentration of 1
mcg/gm of tissue. The limit of detection for tilmicosin in various feline tissues was
determined to be 0.032 mcg/gm. For feline serum, a drug extraction efficiency of 95%
was obtained over a concentration range of 0.15 to 6 mcg/ml after fortification. The
limit of detection was determined to be 0.16 mcg/ml with linearity extending from 0.15
to 6 mcg/ml.
Preparation of Tissue Samples
[0043] Tissue samples were prepared by mincing with scissors or a scalpel on a
paper towel. 10 ml of methanol was added to each tube and the samples homogenized
separately for 10 to 15 minutes. Samples were sonicated on ice for one minute and
centrifuged at 10,000 rpm for 30 minutes at 4 C. The methanol extract was decanted into
fresh centrifuge tubes and the tissue samples resuspend in the tubes with 10 mL of
methanol and 5.0 mL of 100 mM phosphate. The tubes were vortexed and centrifuged at
10,000 rpm for 30 minutes at 4 C. The extract was decanted into fresh centrifuge tubes
and centrifuged at 5000 rpms for 10 minute at 4 C. The methanol extract was added to
70 mL of water in a flask and swirled in the flask to mix.
[0044] Each pool of extracts was loaded to a solid phase extraction C18 Sep-Pak
Plus® (SPE) cartridge (Waters, Milford, MA) using a vacuum manifold or hydrostatic
pump to draw the pools through the cartridges. Once sample were completely loaded,
each SPE cartridge was washed with 10 mL of water, and then with 10 mL of 25%
acetonitrile / water at a flow rate of less than 5 mL / minute. The SPE cartridges were
disconnected from the apparatus and dried completely under high vacuum (26 in. Hg) in
a vacuum desiccation jar for 10 minutes.
[0045] Analyte was eluted from the SPE cartridges with 5% acetic
acid/methanol. Only the first 2.0 mL of eluate was collected. The volumetric flasks
were inverted and mixed, and stored overnight at 4 C.
[0046] The sample eluates were filtered through a 0.22 urn PVDF filter, and
analyzed by HPLC on a SphereClone® 5 um phenyl column (Phenomenex, Torrance,
CA).
[0047] Fluoxetine is a selective serotonin reuptake inhibitor and is extensively
used to treat psychological disorders such as obsessive-compulsive disorder in humans.
It is shown that fluoxetine is effective for treating aggressive behavior and separation
anxiety in dogs and urine spraying behavior in cats. Fluoxetine is formulated at 100 and
150 mg/ml as a lauric acid salt in 10% propylene glycol in glycerol formal in 1:1 drug to
fatty acid ratio. In vitro release kinetics were studied for both formulations at 100
mg/mL concentration using the dialysis technique described in Example 1, and the
results presented in Fig 6. Fluoxetine base in 10% propylene glycol in glycerol formal
at 100 mg/ml is used as a control in the experiment. While the fluoxetine base
formulation is released for about 160 hrs, the 1:1 (drug:LA) lauric acid salt formulation
was released for 700 hrs.
[0048] The fatty acid salt formulation with 1:1.1 fluoxetine to lauric acid ratio at
150 mg/mL concentration was injected sub cutaneous into cats at 20 and 30 mg/kg. At
the same time two cats were dosed at 1 mg/kg/day orally for 28 days. Serum samples
were collected through day 42 and analyzed for fluoxetine by HPLC using 35%
acetonitrile in phosphate buffer, pH 2.7 on a C18 column. The results suggest that a
single sub cutaneous injection of fatty acid salt formulation provide drug concentrations
comparable to daily oral dose through 42 days (Fig. 7).
[0049] The fluoxetine was also formulated as linoleic acid salt in 10% propylene
glycol in glycerol formal, yielding a clear solution. This formulation was also found to
precipitate in water.
Example 8 - Roxithromycin:
[0050] Roxithromycin is an antibiotic in the macrolide class with the following
structure:
[0051] It is effective against a broad range of bacteria, and is used for the
treatment of respiratory diseases in cattle. The amine group of roxithromycin was
neutralized with linoleic acid in 10% propylene in glycerol formal, resulting in a clear
solution at 200 mg/ml. As in the case of tilmicosin, the salt precipitated when the
solution was spiked in water.
Example 9 - Turbinafine
[0052] Turbinafine is an antifungal and the structure is as shown below:
[0053] Turbinafine is a specific inhibitor of squaline epoxidase, ? key enzyme in
fungal ergosterol biosynthesis. The amine group of turbinafine was neutralized with
linoleic acid in 10% propylene glycol in glycerol formal, resulting in a clear solution at
150 mg/ml. The resulting salt was highly insoluble in water, and precipitated when
spiked into water.
[0054] While the invention has been described and exemplified in sufficient
detail for those skilled in this art to make and use it, various alternatives, modifications,
and improvements should be apparent without departing from the spirit and scope of the
invention.
[0055] One skilled in the art readily appreciates that the present invention is well
adapted to carry out the objects and obtain the ends and advantages mentioned, as well as
those inherent therein. Modifications therein and other uses will occur to those skilled in
the art. These modifications are encompassed within the spirit of the invention and are
defined by the scope of the claims.
(0056] It will be readily apparent to a person skilled in the art that varying
substitutions and modifications may be made to the invention disclosed herein without
departing from the scope and spirit of the invention.
[0057] All patents and publications mentioned in the specification are indicative
of the levels of those of ordinary skill in the art to which the invention pertains.
[0058] The invention illustratively described herein suitably may be practiced in
the absence of any element or elements, limitation or limitations which is not specifically
disclosed herein. The terms and expressions which have been employed are used as
terms of description and not of limitation, and there is no intention that in the use of such
terms and expressions of excluding any equivalents of the features shown and described
or portions thereof, but it is recognized that various modifications are possible within the
scope of the invention claimed. Thus, it should be understood that although the present
invention has been specifically disclosed by preferred embodiments and optional
features, modification and variation of the concepts herein disclosed may be resorted to
by those skilled in the art, and that such modifications and variations are considered to be
within the scope of this invention as defined by the appended claims.
[0059] In addition, where features or aspects of the invention are described in
terms of Markush groups, those skilled in the art will recognize that the invention is also
thereby described in terms of any individual member or subgroup of members of the
Markush group. For example, if X is described as selected from the group consisting of
bromine, chlorine, and iodine, claims for X being bromine and claims for X being
bromine and chlorine are fully described.
[0060] Other embodiments are set forth within the following claims.
1. A composition for administration of a pharmacologically active compound to a mammal,
comprising:
a salt of the pharmacologically active compound with a lipophilic counterion; and a
pharmaceutically acceptable solvent;
combined together to form an injectable composition mat precipitates when injected in
wherein me composition releases the active compound over time when injected into me
mammal.
2. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent is
a water miscible solvent
3. The composition as claimed in claim 1, wherein the pharmacologically active compound is
an antibiotic.
4. The composition as claimed in claim 1, wherein the pharmacologically active compound is
tilmicosin, oxytetracycline, doxycycline, fluoxetine, roxithromycin, turbinafine or metoprolol.
5. The composition as claimed in claim 1, wherein the pharmacologically active compound is
selected from the group consisting of: trimethoprim, neomycin, streptomycin, gentamycin,
dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole, tetracyclines,
sulfonamides and aminoglycosides.
6. The composition as claimed in claim 1, wherein the lipophilic counterion is a C10 -C22
saturated or un-saturated fatty acid.
7. The composition as claimed in claim 1, wherein the lipophilic counterion is a C10 -C18
8. The composition as claimed in claim 7, wherein the fatty acid selected from the group
consisting of: lauric acid, decanoic acid, myristic acid, oleic acid and linoleic acid.
9. The composition as claimed in claim 1, wherein the lipophilic counterion is a
polycarboxylic acid.
10. The composition as claimed in claim 1, wherein the polycarboxylic acid is selected from
the group consisting of: sebacic acid, polysebacic acid, polyaspartic acid, polyacrylic acid, and
polybenzoic acid.
11. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent
is selected from the group consisting of one or a combination of: pyrrolidone, N-methyl
pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbide dimethyl ether,
ethanol, dimethyl sulfoxide, and tetrahydrofurfuryl alcohol.
12. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent
comprises 10% propylene glycol in glycerol formal with or without stabilizers.
13. The composition as claimed in claim 1, wherein the pharmaceutically acceptable solvent
is triacetin.
14. The composition as claimed in claim 1, wherein the pharmacologically active compound
is oxytetracycline, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable
solvent is selected from the group consisting of one or more of polyethylene glycol, propylene
glycol, and glycerol formal.
15. The composition as claimed in claim 1, wherein the pharmacologically active compound
is tilmicosin, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent
is selected from the group consisting of one or more of polyethylene glycol, propylene glycol,
and glycerol formal.
16. A process for preparing a sustained release composition of a pharmacologically active
compound to be administered to a mammal comprising:
providing a salt of a pharmacologically active compound and a lipophilic counterion; and
providing a pharmaceutically acceptable solvent; and
combining the salt of a pharmacologically active compound and a lipophilic counterion
with the pharmaceutically acceptable solvent to provide the sustained release composition.
wherein at least a portion of the sustained release composition precipitates and releases
the active compound over time when the composition is injected into mammal.
17. The process as claimed in claim 16, wherein the pharmaceutically acceptable solvent is a
water miscible solvent.
18. The process as claimed in claim 16, wherein the pharmaceutically active compound is an
antibiotic.
19. The process as claimed in claim 16, wherein the lipophilic counterion is a C10-C18 fatty
acid.
20. The process as claimed in claim 18, wherein the antibiotic is tilmicosin, tetracycline, or
doxycycline.
21. The process as claimed in claim 18, wherein the antibiotic is selected from the group
consisting of: trimethoprim, neomycin, streptomycin, gentamycin, tetracyclines, sulfonamides,
and aminoglycosides.
22. The process as claimed in claim 16 wherein the lipophilic counterion is a fatty acid.
23. The process as claimed in claim 22, wherein the fatty acid is a C10-C22 fatty acid.
24. The process as claimed in claim 23, wherein the fatty acid is selected from the group
consisting of: lauric acid, decanoic acid, myristic acid, oleic acid and linoleic acid.
25. The process as claimed in claim 16, wherein the lipophilic counterion is sebacic acid.
26. The process as claimed in claim 16, wherein the pharmaceutically acceptable solvent is
selected from the group consisting of: pyrrolidone, N-methyl pyrrolidone, polyethylene glycol,
propylene glycol, glycerol formal, isosorbide dimethyl ether, ethanol, dimethyl sulfoxide, and
tetrahydrofurfuryl alcohol.
27. The process as claimed in claim 16, wherein the pharmaceutically acceptable solvent is
triacetin.
28. The process as claimed in claim 16, wherein the pharmacologically active compound is
oxytetracycline, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable
solvent is selected from the group consisting of one or more of polyethylene glycol, propylene
glycol, and glycerol formal.
29. The method as claimed in claim 16, wherein the pharmacologically active compound is
tilmicosin, the lipophilic counterion is decanoic acid, and the pharmaceutically acceptable
slovent is selected from the group consisting of one or more of polyethylene glycol, propylene
glycol, and glycerol formal.
30. A method of manufacturing an injectable formulation for the administration of a
pharmacologically active compound to a mammal comprising,
providing a salt of the pharmacologically active compound with a lipophilic counterion;
providing a pharmaceutically acceptable solvent;
combining the salt and the solvent to form an injectable formulation;
wherein at least a portion of the formulation precipitates and releases the active
compound over time when injected into the mammal.
31. The method as claimed in claim 30, wherein the pharmaceutically acceptable solvent is a
water miscible solvent.
32. The method as claimed in claim 30, wherein the pharmacologically active compound is
an antibiotic.
33. The composition as claimed in claim 30, wherein the antibiotic is tilmicosin,
oxytetracycline, or doxycycline.
34. The method as claimed in claim 30, wherein the lipophilic counterion is a C10 - C18
fatty acid.
35. The method as claimed in claim 34, wherein the fatty acid is selected from the group
consisting of : lauric acid, decanoic acid, and myristic acid.
36. The method as claimed in claim 30, wherein the lipophilic counterion is sebacic acid.
37. The method as claimed in claim 30, wherein the pharmaceutically acceptable solvent is
selected from the group consisting of: pyrrolidone, N-methyl pyrrolidone, polyethylene glycol,
propylene glycol, glycerol formal, isosorbide dimethyl ether, ethanol, dimethyl sulfoxide, and
tetrahydrofurfuryl alcohol.
38. The method as claimed in claim 30, wherein the pharmaceutically acceptable solvent is
triacetin.
39. The method as claimed in claim 30, wherein the pharmacologically active compound is
oxytetracycline, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable
solvent is selected from the group consisting of one or more of polyethylene glycol, propylene
glycol, and glycerol formal.
40. The method as claimed in claim 30, wherein the pharmacologically active compound is
tilmicosin, the lipophilic counterion is lauric acid, and the pharmaceutically acceptable solvent is
selected from the group consisting of one or more of polyethylene glycol, propylene glycol, and
glycerol formal.
41. A composition for administration of a pharmacologically active compound to a mammal,
comprising:
a salt of the pharmacologically active compound with a lipophilic counterion; and
a pharmaceutically acceptable solvent
combined together to form an injectable composition; and
wherein at least a portion of the composition precipitates and releases the active
compound over time when injected into an aqueous environment.
42. The composition as claimed in claim 41, wherein the pharmaceutically acceptable solvent
is water miscible.
43. The composition as claimed in claim 41, wherein the antibiotic is tilmicosin,
oxytetracycline, or doxycycline.
44. The composition as claimed in claim 41, wherein the pharmacologically active
compound is selected from the group consisting of: trimethoprim, neomycin, streptomycin,
gentamycin, dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole,
tetracyclines, sulfonamides and aminoglycosides.
45. The composition as claimed in claim 41, wherein the lipophilic counterion is a C10 - C18
fatty acid.
46. The composition as claimed in claim 45, wherein the fatty acid selected from the group
consisting of: lauric acid, decanoic acid, and myristic acid.
47 The composition as claimed in claim 41, wherein the lipophilic counterion is sebacic
acid.
48. The composition as claimed in claim 41, wherein the pharmaceutically acceptable solvent
is selected from the group consisting of one or a combination of: pyrrolidone, N-methyl
pyrrolidone, polyethylene glycol, propylene glycol, glycerol formal, isosorbide dimethyl ether,
ethanol, dimethyl sulfoxide, and tetrahydrofurfuryl alcohol.
49. The composition as claimed in claim 41, wherein the pharmaceutically acceptable solvent
is triacetin.
50. A composition for administration of a pharmacologically active compound to a mammal,
comprising:
a salt of the pharmacologically active compound with a lipophilic counterion; and
a pharmaceutically acceptable solvent;
combined together to form an injectable composition; and wherein at least a portion of
the pharmaceutically active compound and lipophilic counterion dissolves in the solvent and
precipitates in vivo.
51. A composition for administration of a pharmacologically active compound to a mammal,
comprising:
a salt of the pharmacologically active compound with a polycarboxylic acid counterion;
and
a pharmaceutically acceptable solvent;
combined together to form an injectable composition that precipitates when injected into)
water and
wherein the composition releases the active compound over time when injected into the
mammal.
52. The composition as claimed in claim 51, wherein the polycarboxylic acid is selected from
the group consisting of: polyaspartic acid, polyacrylic acid, sebacic acid, polysebacic acid, and
polybenzoic acid.
53. The composition as claimed in claim 51, wherein the pharmaceutically acceptable solvent
is a water miscible solvent.
54. The composition as claimed in claim 51, wherein the pharmacologically active compound
is an antibiotic.
55. The composition as claimed in claim 51, wherein the pharmacologically active compound
is tilmicosin, oxytetracycline, doxycycline, fluoxetine, roxithromycin, terbinafine or metoprolol.
56. The composing as claimed in claim 51, wherein the pharmacologically active compound
is selected from the group consisting of: trimethoprim, neomycin, streptomycin, gentamycin,
dibucaine, bupivacaine, benzocaine, tetracaine, acepromazine, itraconazole, tetracyclines,
sulfonamides, and aminoglycosides.
The present invention provides compositions and methods for
extending the release times and lowering the toxicity of
pharmacologically active compounds. The compounds comprise a salt
of the pharmacologically active compound with a lipophilic
counterion and a pharmaceutically acceptable water soluble solvent
combined together to form an injectable composition. The
lipophilic counterion may be a saturated or unsaturated C8 - C22
fatty acid, and preferably may be a saturated or unsaturated
C10 - C18 fatty acid. When injected into a mammal, at least a
portion of the composition precipitates and releases the active
compound over time. Thus, the composition forms a slowly releasing
drug depot of the active compound in the mammal. Therefore, the
present invention enables one to provide a controlled dose
administration of the active compound for a periods of up to 15
days or even longer. Many compounds can be administered according
to the present invention including, but not limited to,
tilmicosin, oxytetracycline, metoprolol, fluoxetine,
roxithromycin, and turbinafine.

Documents:

224-kolnp-2004-granted-abstract.pdf

224-kolnp-2004-granted-claims.pdf

224-kolnp-2004-granted-correspondence.pdf

224-kolnp-2004-granted-description (complete).pdf

224-kolnp-2004-granted-drawings.pdf

224-kolnp-2004-granted-form 1.pdf

224-kolnp-2004-granted-form 18.pdf

224-kolnp-2004-granted-form 2.pdf

224-kolnp-2004-granted-form 26.pdf

224-kolnp-2004-granted-form 3.pdf

224-kolnp-2004-granted-form 5.pdf

224-kolnp-2004-granted-letter patent.pdf

224-kolnp-2004-granted-reply first examination report.pdf

224-kolnp-2004-granted-specification.pdf

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Patent Number

218571

Indian Patent Application Number

00224/KOLNP/2004

PG Journal Number

14/2008

Publication Date

04-Apr-2008

Grant Date

02-Apr-2008

Date of Filing

18-Feb-2004

Name of Patentee

IDEXX LABORATORIES, INC.

Applicant Address

ONE IDEXX DRIOVE, WESTBROOK, ME 04092 USA.

Inventors:

#	Inventor's Name	Inventor's Address
1	MURTHY YERRAMILLI V.S.A	2212 OAK STREAM LANE APEX, NC 27535 USA.
2	SUVA ROBERT	215 ROPE ROAD WINDHAM, ME 04062 USA.

PCT International Classification Number

A61K9/00

PCT International Application Number

PCT/US02/33300

PCT International Filing date

2002-10-18

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60,343, 625	2002-10-19	U.S.A.