Title of Invention	"COMPLEX CONTAINING MEQUITAZINE, A CYCLODEXTRIN AND AN INTERACTION AGENT"
Abstract	The present invention relates to a complex that includes mequitazine, a cyclodextrin, and an interaction agent wherein the rate of solubilization in water of complexed mequitazine, measured for a 2 g/1 mixture of mequitazine in water at 35 °C after 15 minutes of stirring, is greater than 50% at pH 9. The present invention also relates to a method of preparing the aforementioned complex and a pharmaceutical composition of which the complex is a part.

Title of Invention

"COMPLEX CONTAINING MEQUITAZINE, A CYCLODEXTRIN AND AN INTERACTION AGENT"

Abstract

The present invention relates to a complex that includes mequitazine, a cyclodextrin, and an interaction agent wherein the rate of solubilization in water of complexed mequitazine, measured for a 2 g/1 mixture of mequitazine in water at 35 °C after 15 minutes of stirring, is greater than 50% at pH 9. The present invention also relates to a method of preparing the aforementioned complex and a pharmaceutical composition of which the complex is a part.

Full Text	TITLE: A COMPLEX COMPRISING MEQUITAZINE, A CYCLODEXTRIN, AND AN INTERACTION AGENT The present invention relates to complexes of mequitazine, cyclodextrins, and an interaction agent, as such complexes have much higher solubility compared to mequitazine considered alone. Numerous pharmaceutically active substances present low solubility in aqueous media and consequently in biological media. Such solubility leads to low bioavailability and as a result doses administered must be increased. Such an increase is not always without consequences both with respect to side effects as well as from an economic point of view when considering the high cost of the pharmaceutically active ingredients. Mequitazine is an antihistamine used for the treatment of allergies. The mequitazine molecule was specifically described in patent FR 2 034 605. Mequitazine is generally administered by oral route in a variety of forms such as syrup, tablets, or gel caps, for example. As for many pharmaceutically active ingredients, the absorption of mequitazine administered by oral route takes place in the intestine. However, it has been observed by the applicant that the bioavailability of this active ingredient is very low, on the order of 0.3%, which could be explained by its low solubility. A very small portion of the mequitazine ingested is in solubilized form, and thus it is absorbed with difficulty through the intestinal barrier. There are various pharmaceutical publications and patents relating to the production of interaction complexes of active ingredients with cyclodextrins, and this with the aim of improving their solubility. However, none specifically relates to mequitazine in the form of a racemic mixture or of one of its enantiomers. Patent FR 2 742 053 describes an aqueous formulation intended for the local treatment of ocular allergies. The patent also describes a collyrium that includes mequitazine and cyclodextrins in an aqueous solution. As indicated in an example in the patent, the pH of the ready-to-use collyrium described therein is adjusted to 6, a value that enables it alone to ensure complete dissolution of mequitazine. Moreover, mequitazine and cyclodextrin are simply mixed in the aqueous medium and by no means is a complex created. Moreover, no interaction agent is used. The collyrium described in the patent is neither intended for oral administration nor to be subjected to a change in pH. Lastly, no allusion is made as to the bioavailability of mequitazine. Indeed, in the aforementioned document this problem does not arise because it involves local application to the eye and not administration orally. Thus it should be noted that there is a need with regard to a pharmaceutical formulation containing mequitazine as an active ingredient which overcomes the low bioavailability of the current formulations which result from the low solubility of mequitazine when administered orally. With regard to the simple manufacture of a medicine such as a syrup, solubility is not an obstacle to the formulation of mequitazine because mequitazine presents high solubility in an acid pH range from 2 to 6. Thus, for a liquid formulation such as described in FR 2 742 053, it is sufficient to be placed in an acid pH range to ensure complete mequitazine solubility. On the other hand, as neutrality is approached then surpassed, solubility breaks down, and it is in this case that the difficulties related to solubility and bioavailability arise since, as stated above, the pH of the intestinal juce is in an approximate range of 7 to 9. The aim of the present invention thus consists of providing a solid form of mequitazine that presents a satisfactory solubility in an extended pH range, in particular at basic pH. Thus, in the cases measured here, solubility is most often measured at a pH of approximately 9. The present invention thus has as an aim a complex that includes mequitazine, a cyclodextrin, and an interaction agent wherein the rate of solubilization in water of complexed mequitazine measured for a 2 g/1 mixture of mequitazine in water at 35 °C after 15 minutes of stirring, is greater than 50% at pH 9. The mequitazine/cyclodextrin/interaction agent complex according to the present invention is in solid form. The mequitazine contained in the complexes according to the present invention can be presented in racemic form or enantiomer form, namely L-mequitazine or D-mequitazine. The present invention thus relates to complexes of a cyclodextrin and racemic mequitazine, complexes of a cyclodextrin and Dmequitazine, and/or complexes of a cyclodextrin and Lmequitazine, all of these complexes including moreover an interaction agent. Additionally, it has been noted that when the complexes involve one mequitazine enantiomer only, either D- or L-, the rate of solubilization in water of complexed mequitazine according to the present invention is advantageously greater than 60% at pH 9, more advantageously greater than 70% at pH 9. Moreover, it has been noted that when the complexes involve the L- enantiomer only, the rate of solubilization in water of the complexed mequitazine according to the present invention is advantageously greater than 80% at pH 9. Such complexes make it possible to propose and formulate mequitazine in soluble form, therefore easily assimilable, across the physiological pH range and in particular at a pH of approximately 7 to 10 and more advantageously of approximately 8 to 9. Indeed, as previously indicated, the pH of the intestinal milieu ranges between approximately 7 and approximately 9, and it is precisely there that mequitazine is absorbed. The fact of ensuring a particularly increased solubility at these pH is an undeniable advantage of the present invention. As an indication, measured under the same conditions, the rate of solubilization of mequitazine alone, which is to say not complexed, is about 1%. Thus, the present invention makes it possible to increase the solubility of this molecule by a factor of at least 30, even 60, and even 80. Thus, the addition of an interaction agent to the mequitazine/cyclodextrin complex according to the present invention makes it possible to increase the solubilization of mequitazine. In the sense of the present invention, "interaction agent" means any organic or mineral agent that improves the physicochemical properties, in particular the properties of solubilization in aqueous media, of the mequitazine/cyclodextrin complex by noncovalent interactions with the mequitazine included in the cyclodextrin or directly with the mequitazine/cyclodextrin complex. Advantageously, the interaction agent is either a surfactant, for example sodium laurel sulfate or Tween, an acid, or a base. Advantageously, it is an acid or a base. In an advantageous way, the interaction agent is selected from among an amino acid, a carboxylic acid, an acetate, a carboxylate, an amine, or ammonia. In an even more advantageous way, is selected from among acetic acid, tartaric acid, citric acid, gluconic acid, malic acid, lactic acid, maleic acid, fumaric acid, L-lysine, L-valine, L-isoleucine, L-arginine, and ammonia. Advantageously, it is an amino acid, in an advantageous way a basic amino acid. Arginine is particularly preferred, advantageously in its L- form. The present invention also relates to the use of the complex according to the present invention to increase the solubility and the bioavailability of mequitazine at basic pH, advantageously in the range between 7 and 10, and in an advantageous way still between 8 and 9. The preferred interaction agent is arginine, and the invention thus relates to mequitazine/ cyclodextrin/ arginine complexes and their use to increase mequitazine solubility and bioavailability at basic pH, advantageously in the range between 7 and 10, and in 'an advantageous way still between 8 and 9. Advantageously the cyclodextrin is selected from among the group consisting of the cyclodextrins, modified cyclodextrins, and their mixture. In an advantageous way, it is (3- cyclodextrin, methyl-(3-cyclodextrin, Y~cyclodex.tr in, or hydroxypropyl-(3-cyclodextrin. Advantageously, it is (3- cyclodextrin. In the sense of the present invention, "rate of solubilization" means the percentage of solubilized mequitazine after stirring a mixture of water and mequitazine for 15 minutes at 37 °C. A mixture of 2 g/1 of mequitazine in water is usually used to measure this rate. This solubilization can be measured by a solubilization test as indicated below. MEQUITAZINE SOLUBILIZATION TEST Experimental protocol: The mequitazine content in the dissolution solutions is measured by HPLC: Equipment used: Waters HPLC system: - Separation module 2695, - UV detector 2487. Chromatographic conditions: Column: uBondapak 125A, 10 jam, 150 x 4.6 mm Mobile phase: - 90%: 500 ml water / 500 ml acetonitrile / 1 ml phosphoric acid, - 10%: 500 ml water / 0.5 ml phosphoric acid. Flow rate: 1 ml/min Wavelength detector: 256 nm Detector sensitivity: 2 AUFS Volume injected: 20 ul Oven temperature: 25 °C Analysis period: 12 minutes Preparation of the control solutions: Control solution: SM: Place 50 mg of control mequitazine in a 100 ml flask. Dissolve with 20 ml of dimethylformamide and bring up to volume with methanol. Range: Tl: 1:20 dilution of T3 in water/acetonitrile (50/50), T2: 1:10 dilution of T3 in water/acetonitrile (50/50), T3: 1:100 dilution of SM in water/acetonitrile (50/50), T4: 1:50 dilution of SM in water/acetonitrile (50/50), T5: 1:20 dilution of SM in 50% water/50% acetonitrile. Procedure for solubility tests at 2 g/1: Test procedure: In a 100 ml Erlenmeyer flask, place a test sample equivalent to 100 mg of mequitazine. Add 50 ml of ultrapure water. The pH obtained is approximately 9.5. Place under magnetic stirring at 400 rpm in a water bath at 37 °C ± 2 °C. Remove a 2 ml sample under magnetic stirring at 15 minutes. Filter the sample on a 0.45 urn Gelman GHP Acrodisc polypropylene filter. The solution must be limpid. Dilute the sample to 1/200 in a phase: water/acetonitrile (50/50). Methodology, presentation of results: Inject 20 ul of each control solution. Perform a linear regression of the mequitazine peak surfaces with respect to the concentrations. The correlation coefficient must be greater than 0.995. Inject 20 pi of the solutions to be examined. Measure the area of the peak of mequitazine in each solution to be examined. Deduce concentration X in ug/ml by following the regression line of the controls. Calculate the concentration in ug/ml of solubilized mequitazine by multiplying by the inverse of the dilution made (i.e., 200). The rate of solubility of mequitazine is calculated by dividing the concentration of solubilized mequitazine by the total concentration of mequitazine in the starting solution. The mequitazine/ cyclodextrin/ interaction agent complexes are likely to be obtained by a process such as described hereafter. A method of preparing a complex according to the present invention includes the following successive steps: a) placing mequitazine in contact with a cyclodextrin and an interaction agent; b) implementing a molecular diffusion step by placing in contact in static mode a dense fluid under pressure with the mixture obtained in step (a) in the presence of one or more diffusion agents; c) recovering the mequitazine/ cyclodextrin/ interaction agent complex thus formed. The complex thus recovered in step (c) is in solid form. However, it may still contain some water molecules or be moist. In order to eliminate any trace of water, in another advantageous embodiment, step (c) is followed by a step (d) of drying the complex, advantageously between 60 °C and 80 °C, advantageously at 60 °C and in an advantageous way overnight. This drying, which is optional, thus makes it possible to remove any trace of residual water present in the complex following step (c). The step of molecular diffusion in static mode, step (b) termed the maturation step, essentially consists of a molecular diffusion phase in a dense milieu under pressure, and in particular supercritical, that enables mequitazine to be included in cyclodextrins. The objective sought during this phase of diffusion is to form inclusion complexes between mequitazine, the cyclodextrin, and the interaction agent. The complex thus formed associates mequitazine, the cyclodextrin, and the interaction agent noncovalently. The interaction agent interacts according to two plausible hypotheses: strong interactions with the mequitazine included in the cyclodextrin and/or strong interactions with the complex formed. The presence of this interaction agent primarily makes it possible to improve the dissolution properties of the complex in biological liquids, in particular water, and to possibly increase the rate of inclusion of mequitazine in the cyclodextrin. The improvement of the physicochemical properties, in particular in terms of dissolution of the system formed may originate in: - noncovalent interaction of the interaction agent with mequitazine, the cyclodextrin, or both (complexation, salification, etc.)/ - local pH variation in the dissolution medium, - presence of an eutectic system, - modification of the interface between the system and its dissolution medium (surfactant effect, granulometric change). In the sense of the present invention, "dense fluid under pressure" means any fluid used at a temperature or a pressure greater than its critical value. Advantageously C02 may be used pure or as mixture with an organic solvent classically used by those skilled in the art. In the sense of the present invention, "diffusion agent" means any solvent that favors an interaction of mequitazine with a cyclodextrin. Advantageously, this diffusion agent is selected from among the group consisting of the alcohols, ketones, ethers, esters, and water, with or without a surfactant, and their mixtures. In an even more advantageous way, water is selected. In the sense of the present invention, "static mode" means a reaction or a process in which all of the reagents are simultaneously placed together and where the reaction is allowed to progress. For example, in step (b) of the present invention, into an autoclave are placed the substances of the complex, water, and supercritical C02, and the reaction is allowed to progress for several hours. The mass of the product does not change during the reaction. On the contrary, in dynamic mode, the reagents are supplied as the reaction or production progresses. Often within the framework of dynamic mode, there is circulation of a fluid. The mass of the product changes during production. In an advantageous way, molecular diffusion step (b) of the method according to the present invention is carried out under stirring. In a particular embodiment of the invention, during step (a) mequitazine, the interaction agent, and the cyclodextrin are introduced in solid or liquid form into a receptacle into which during step (b) is injected the dense fluid under pressure and the diffusion agent in judiciously selected proportions. Pressure and temperature conditions, as well as the duration of treatment, are defined by any suitable method. The diffusion agent can be added continuously or discontinuously in a quantity ranging between 1 and 50% in mass compared to the total mass of the mixture, preferably between 10 and 25% in mass compared to total mass of the mixture. The time necessary for the molecular diffusion in step (b) is determined by any suitable method. Step (b) may be repeated as many times as desired to obtain a satisfactory rate of dissolution. Advantageously, step (b) lasts between approximately 1 and 16 hours, advantageously 2 hours. The pressure and temperature conditions in step (b) are chosen in a way to favor molecular diffusion. Advantageously the pressure of the supercritical fluid lies between 0.5 MPa and 50 MPa, advantageously 15 MPa, and the temperature between 0 and 200 °C, advantageously 75 °C. Advantageously step (b) of the process is implemented in a closed reactor, in particular an autoclave. The process can be implemented in batches or continuously. In an advantageous way the process according to the present invention is carried out in batches. The mequitazine/cyclodextrin/interaction agent molar ratio can be chosen in a way to ensure optimal inclusion of mequitazine within the cyclodextrins. Thus, advantageously the mequitazine/cyclodextrin molar ratio lies between 1/1 and 1/10, advantageously between 1/1 and 1/5, and in an advantageous way between 1/2 and 1/3. In the same advantageous way the mequitazine/interaction agent molar ratio lies between 1/1 and 1/10, advantageously between 1/1 and 1/5, and in an advantageous way between 1/1 and 1/3. Advantageously, step (b) of the process is implemented in a closed reactor, possibly under stirring, supplied with the dense fluid and the mequitazine solution, continuously if need be. The present invention relates moreover to a pharmaceutical composition, intended to be administered by oral route, that includes a complex according to the present invention, and possibly a pharmaceutically acceptable excipient. It concerns moreover a complex according to the present invention or a pharmaceutical composition according to the present invention for its use as a drug, advantageously intended to treat allergies. The following examples, given as indications, were carried out with mequitazine in racemic form and/or D- or L- enantiomer form, with the additional use of \|3-cyclodextrin, water as a diffusion agent, and arginine as an interaction agent. COMPARATIVE EXAMPLE 1: Creation of mequitazine/(3-cyclodextrin complexes. 2.5 grams of mequitazine in racemic or L- or D- form, 20.11 grams of (3-cyclodextrin, and 5.11 grams of water are mixed and introduced into a 500 ml reactor. Carbon dioxide is then introduced into the reactor under a pressure of 15 MPa and at a temperature of 75 °C. The unit is maintained under these operating conditions for 2 hours. The powder thus collected after releasing the medium is placed in a drying oven at 60 °C overnight. The solubility and the rates of solubilization of complexed mequitazine (D, L, or racemic) are measured as indicated above in the "mequitazine solubilization test". The results are collected in Table 1 and represented in Figure 1 below. EXAMPLE 2: Creation of mequitazine/ft-cyclodextrin/arginine complexes. The procedure is identical to that of Example 1, only the quantities of the reagents change. 2.5 grams of mequitazine in racemic or L- or D- form, 20.11 grams of \|3-cyclodextrin, 1.35 grams of arginine, and 5.63 grams of water are used. The solubility and the rates of solubilization of complexed mequitazine (D, L, or racemic) are measured as indicated above in the "mequitazine solubilization test". The results are collected in Table 1 and represented in Figure 1 below. COMPARATIVE EXAMPLE: Solubility of racemic, L-, and Dmequitazine taken separately and physical mixtures of mequitazine/(3-cyclodextrin and mequitazine/ftcyclodextrin/ arginine. Moreover, the rates of solubilization of the mequitazine obtained thanks to the use of the complexes according to the present invention are compared with the rates of solubilization obtained with the simple cyclodextrin/mequitazine mixture and optionally an interaction agent, such a mixture is called a "physical mixture" and has nothing in common with complexes. Creation of a "physical mixture": A "physical mixture" corresponds to the simple mixture of the components but in a non-complexed form. It is thus a question of using the molar ratios of mequitazine/cyclodextrin and possibly arginine as interaction agent used to create the complexes, and to carry out solubility tests on these "physical mixtures". Thus the superiority of the complexes according to the present invention can be demonstrated, in particular compared to simple physical mixtures which correspond, for example, to the product described in patent application FR 2 742 053. The solubility and the rates of solubilization of mequitazine only or mequitazine in physical mixtures are measured as indicated above in the "mequitazine solubilization test". The solubilization results are collected in Table 1 and represented in Figure 1 below. 14 Table 1: Rate of solubilization of mequitazine in the various samples: mequitazine alone, in a simple physical mixture, or in complex with cyclodextrin or cyclodextrin and arginine. (Table Removed) Figure 1 represents the rates of solubilization of mequitazine for the various samples tested at 37 °C after 15 minutes of stirring for a 2 g/1 solution of mequitazine. Thus it can be noted that the complexes according to the present invention allow a particularly increased mequitazine solubility, to be specific at pH 9. Such a pH is particularly interesting because it corresponds to intestinal pH. It can also be noted that mequitazine alone has a very low solubility at this pH. A difference in solubility between racemic mequitazine and when complexed with either enantiomer can also be noted. It appears that in the complexed form the enantiomer complexes have the best solubility. It is also observed that the simple physical component mixtures, even if they make it possible to increase the rate of dissolution of mequitazine, do not make it possible to obtain results as satisfactory as those obtained with the complexes. Thus, with the complexes, the rate of dissolution is increased by a factor of approximately 3. In the same way, simple complexation without an interaction agent does not make it possible to obtain results as satisfactory as those obtained with the complexes according to the present invention. CLAIMS 1. A complex that includes mequitazine, a cyclodextrin, and an interaction agent wherein the rate of solubilization in water of complexed mequitazine, measured for a 2 g/1 mixture of mequitazine in water at 35 °C after 15 minutes of stirring, is greater than 50% at pH 9. 2. A complex according to claim 1, wherein mequitazine is in the form of only one enantiomer D- or L- and wherein the rate of solubilization in water of complexed mequitazine measured for a 2 g/1 mixture of mequitazine in water at 35 °C after 15 minutes of stirring, is greater than 60% at pH 9, advantageously greater than 70% at pH 9. 3. A complex according to claim 2, wherein mequitazine is in the form of its L- enantiomer and wherein the rate of solubilization in water of complexed mequitazine measured for a 2 g/1 mixture of mequitazine in water at 35 °C after 15 minutes of stirring, is greater than 80% at pH 9. 4. A complex according to any of the preceding claims, wherein the interaction agent is L-arginine. 5. A method of preparing a complex according to any of claims 1 to 4 wherein it comprises the following successive stages: a) placing mequitazine in contact with a cyclodextrin and an interaction agent; b) implementing a molecular diffusion step by placing in contact in static mode a dense fluid under pressure with the mixture obtained in step (a) in the presence of one or more diffusion agents; c) recovering the mequitazine/cyclodextrin/ interaction agent complex thus formed. 6. A process according to claim 5 wherein it includes an additional step (d) of drying the complex, advantageously at a temperature ranging between 60 and 80 °C. 7. A process according to claim 5 or claim 6 wherein the dense fluid under pressure is carbon dioxide. 8. A process according to any of claims 5 to 7 wherein the diffusion agent is selected from among the group comprising the alcohols, ketones, ethers, esters, and water, with or without surfactant agent, and their mixtures, advantageously the selection is water. 9. A process according to any of claims 5 to 8 wherein molecular diffusion step (b) is carried out under stirring. 10. A process according to any of claims 5 to 9 wherein the diffusion agent is added continuously or discontinuously in a quantity ranging between 1 and 25% in mass, preferably between 10 and 25% in mass. 11. A process according to any of claims 5 to 10 wherein the mequitazine/cyclodextrin molar ratio lies between 1/1 and 1/10, advantageously between 1/1 and 1/5, in an advantageous way between 1/2 and 1/3. 12. A process according to any of claims 5 to 11 wherein the mequitazine/interaction agent molar ratio lies between 1/1 and 1/10, advantageously between 1/1 and 1/5, in an advantageous way between 1/1 and 1/3. 13. A pharmaceutical composition, intended to be administered by oral route, that includes a complex according to any of claims 1 to 4. 14. A complex according to any of the claims 1 to 4 or a pharmaceutical composition according to claim 13 for use as a drug, advantageously intended to treat allergies.

Full Text

TITLE: A COMPLEX COMPRISING MEQUITAZINE, A CYCLODEXTRIN, AND
AN INTERACTION AGENT
The present invention relates to complexes of mequitazine,
cyclodextrins, and an interaction agent, as such complexes
have much higher solubility compared to mequitazine considered
alone.
Numerous pharmaceutically active substances present low
solubility in aqueous media and consequently in biological
media. Such solubility leads to low bioavailability and as a
result doses administered must be increased. Such an increase
is not always without consequences both with respect to side
effects as well as from an economic point of view when
considering the high cost of the pharmaceutically active
ingredients.
Mequitazine is an antihistamine used for the treatment of
allergies. The mequitazine molecule was specifically described
in patent FR 2 034 605.
Mequitazine is generally administered by oral route in a
variety of forms such as syrup, tablets, or gel caps, for
example.
As for many pharmaceutically active ingredients, the
absorption of mequitazine administered by oral route takes
place in the intestine. However, it has been observed by the
applicant that the bioavailability of this active ingredient
is very low, on the order of 0.3%, which could be explained by
its low solubility. A very small portion of the mequitazine
ingested is in solubilized form, and thus it is absorbed with
difficulty through the intestinal barrier.
There are various pharmaceutical publications and patents
relating to the production of interaction complexes of active
ingredients with cyclodextrins, and this with the aim of
improving their solubility. However, none specifically relates
to mequitazine in the form of a racemic mixture or of one of
its enantiomers.
Patent FR 2 742 053 describes an aqueous formulation intended
for the local treatment of ocular allergies. The patent also
describes a collyrium that includes mequitazine and
cyclodextrins in an aqueous solution. As indicated in an
example in the patent, the pH of the ready-to-use collyrium
described therein is adjusted to 6, a value that enables it
alone to ensure complete dissolution of mequitazine. Moreover,
mequitazine and cyclodextrin are simply mixed in the aqueous
medium and by no means is a complex created. Moreover, no
interaction agent is used. The collyrium described in the
patent is neither intended for oral administration nor to be
subjected to a change in pH. Lastly, no allusion is made as to
the bioavailability of mequitazine. Indeed, in the
aforementioned document this problem does not arise because it
involves local application to the eye and not administration
orally.
Thus it should be noted that there is a need with regard to a
pharmaceutical formulation containing mequitazine as an active
ingredient which overcomes the low bioavailability of the
current formulations which result from the low solubility of
mequitazine when administered orally.
With regard to the simple manufacture of a medicine such as a
syrup, solubility is not an obstacle to the formulation of
mequitazine because mequitazine presents high solubility in an
acid pH range from 2 to 6. Thus, for a liquid formulation such
as described in FR 2 742 053, it is sufficient to be placed in
an acid pH range to ensure complete mequitazine solubility. On
the other hand, as neutrality is approached then surpassed,
solubility breaks down, and it is in this case that the
difficulties related to solubility and bioavailability arise
since, as stated above, the pH of the intestinal juce is in an
approximate range of 7 to 9.
The aim of the present invention thus consists of providing a
solid form of mequitazine that presents a satisfactory
solubility in an extended pH range, in particular at basic pH.
Thus, in the cases measured here, solubility is most often
measured at a pH of approximately 9.
The present invention thus has as an aim a complex that
includes mequitazine, a cyclodextrin, and an interaction agent
wherein the rate of solubilization in water of complexed
mequitazine measured for a 2 g/1 mixture of mequitazine in
water at 35 °C after 15 minutes of stirring, is greater than
50% at pH 9.
The mequitazine/cyclodextrin/interaction agent complex
according to the present invention is in solid form.
The mequitazine contained in the complexes according to the
present invention can be presented in racemic form or
enantiomer form, namely L-mequitazine or D-mequitazine. The
present invention thus relates to complexes of a cyclodextrin
and racemic mequitazine, complexes of a cyclodextrin and Dmequitazine,
and/or complexes of a cyclodextrin and Lmequitazine,
all of these complexes including moreover an
interaction agent.
Additionally, it has been noted that when the complexes
involve one mequitazine enantiomer only, either D- or L-, the
rate of solubilization in water of complexed mequitazine
according to the present invention is advantageously greater
than 60% at pH 9, more advantageously greater than 70% at pH
9.
Moreover, it has been noted that when the complexes involve
the L- enantiomer only, the rate of solubilization in water of
the complexed mequitazine according to the present invention
is advantageously greater than 80% at pH 9.
Such complexes make it possible to propose and formulate
mequitazine in soluble form, therefore easily assimilable,
across the physiological pH range and in particular at a pH of
approximately 7 to 10 and more advantageously of approximately
8 to 9. Indeed, as previously indicated, the pH of the
intestinal milieu ranges between approximately 7 and
approximately 9, and it is precisely there that mequitazine is
absorbed. The fact of ensuring a particularly increased
solubility at these pH is an undeniable advantage of the
present invention. As an indication, measured under the same
conditions, the rate of solubilization of mequitazine alone,
which is to say not complexed, is about 1%. Thus, the present
invention makes it possible to increase the solubility of this
molecule by a factor of at least 30, even 60, and even 80.
Thus, the addition of an interaction agent to the
mequitazine/cyclodextrin complex according to the present
invention makes it possible to increase the solubilization of
mequitazine.
In the sense of the present invention, "interaction agent"
means any organic or mineral agent that improves the
physicochemical properties, in particular the properties of
solubilization in aqueous media, of the
mequitazine/cyclodextrin complex by noncovalent interactions
with the mequitazine included in the cyclodextrin or directly
with the mequitazine/cyclodextrin complex. Advantageously, the
interaction agent is either a surfactant, for example sodium
laurel sulfate or Tween, an acid, or a base. Advantageously,
it is an acid or a base.
In an advantageous way, the interaction agent is selected from
among an amino acid, a carboxylic acid, an acetate, a
carboxylate, an amine, or ammonia. In an even more
advantageous way, is selected from among acetic acid, tartaric
acid, citric acid, gluconic acid, malic acid, lactic acid,
maleic acid, fumaric acid, L-lysine, L-valine, L-isoleucine,
L-arginine, and ammonia. Advantageously, it is an amino acid,
in an advantageous way a basic amino acid. Arginine is
particularly preferred, advantageously in its L- form.
The present invention also relates to the use of the complex
according to the present invention to increase the solubility
and the bioavailability of mequitazine at basic pH,
advantageously in the range between 7 and 10, and in an
advantageous way still between 8 and 9. The preferred
interaction agent is arginine, and the invention thus relates
to mequitazine/ cyclodextrin/ arginine complexes and their use
to increase mequitazine solubility and bioavailability at
basic pH, advantageously in the range between 7 and 10, and in
'an advantageous way still between 8 and 9.
Advantageously the cyclodextrin is selected from among the
group consisting of the cyclodextrins, modified cyclodextrins,
and their mixture. In an advantageous way, it is (3-
cyclodextrin, methyl-(3-cyclodextrin, Y~cyclodex.tr in, or
hydroxypropyl-(3-cyclodextrin. Advantageously, it is (3-
cyclodextrin.
In the sense of the present invention, "rate of
solubilization" means the percentage of solubilized
mequitazine after stirring a mixture of water and mequitazine
for 15 minutes at 37 °C. A mixture of 2 g/1 of mequitazine in
water is usually used to measure this rate. This
solubilization can be measured by a solubilization test as
indicated below.
MEQUITAZINE SOLUBILIZATION TEST
Experimental protocol:
The mequitazine content in the dissolution solutions is
measured by HPLC:
Equipment used:
Waters HPLC system:
- Separation module 2695,
- UV detector 2487.
Chromatographic conditions:
Column: uBondapak 125A, 10 jam, 150 x 4.6 mm
Mobile phase:
- 90%: 500 ml water / 500 ml acetonitrile / 1 ml phosphoric
acid,
- 10%: 500 ml water / 0.5 ml phosphoric acid.
Flow rate: 1 ml/min
Wavelength detector: 256 nm
Detector sensitivity: 2 AUFS
Volume injected: 20 ul
Oven temperature: 25 °C
Analysis period: 12 minutes
Preparation of the control solutions:
Control solution: SM: Place 50 mg of control mequitazine in a
100 ml flask. Dissolve with 20 ml of dimethylformamide and
bring up to volume with methanol.
Range:
Tl: 1:20 dilution of T3 in water/acetonitrile (50/50),
T2: 1:10 dilution of T3 in water/acetonitrile (50/50),
T3: 1:100 dilution of SM in water/acetonitrile (50/50),
T4: 1:50 dilution of SM in water/acetonitrile (50/50),
T5: 1:20 dilution of SM in 50% water/50% acetonitrile.
Procedure for solubility tests at 2 g/1:
Test procedure:
In a 100 ml Erlenmeyer flask, place a test sample equivalent
to 100 mg of mequitazine. Add 50 ml of ultrapure water. The pH
obtained is approximately 9.5. Place under magnetic stirring
at 400 rpm in a water bath at 37 °C ± 2 °C. Remove a 2 ml
sample under magnetic stirring at 15 minutes. Filter the
sample on a 0.45 urn Gelman GHP Acrodisc polypropylene filter.
The solution must be limpid. Dilute the sample to 1/200 in a
phase: water/acetonitrile (50/50).
Methodology, presentation of results:
Inject 20 ul of each control solution.
Perform a linear regression of the mequitazine peak surfaces
with respect to the concentrations. The correlation
coefficient must be greater than 0.995.
Inject 20 pi of the solutions to be examined.
Measure the area of the peak of mequitazine in each solution
to be examined.
Deduce concentration X in ug/ml by following the regression
line of the controls.
Calculate the concentration in ug/ml of solubilized
mequitazine by multiplying by the inverse of the dilution made
(i.e., 200).
The rate of solubility of mequitazine is calculated by
dividing the concentration of solubilized mequitazine by the
total concentration of mequitazine in the starting solution.
The mequitazine/ cyclodextrin/ interaction agent complexes are
likely to be obtained by a process such as described
hereafter.
A method of preparing a complex according to the present
invention includes the following successive steps:
a) placing mequitazine in contact with a cyclodextrin and an
interaction agent;
b) implementing a molecular diffusion step by placing in
contact in static mode a dense fluid under pressure with
the mixture obtained in step (a) in the presence of one
or more diffusion agents;
c) recovering the mequitazine/ cyclodextrin/ interaction
agent complex thus formed.
The complex thus recovered in step (c) is in solid form.
However, it may still contain some water molecules or be
moist. In order to eliminate any trace of water, in another
advantageous embodiment, step (c) is followed by a step (d) of
drying the complex, advantageously between 60 °C and 80 °C,
advantageously at 60 °C and in an advantageous way overnight.
This drying, which is optional, thus makes it possible to
remove any trace of residual water present in the complex
following step (c).
The step of molecular diffusion in static mode, step (b)
termed the maturation step, essentially consists of a
molecular diffusion phase in a dense milieu under pressure,
and in particular supercritical, that enables mequitazine to
be included in cyclodextrins. The objective sought during this
phase of diffusion is to form inclusion complexes between
mequitazine, the cyclodextrin, and the interaction agent.
The complex thus formed associates mequitazine, the
cyclodextrin, and the interaction agent noncovalently.
The interaction agent interacts according to two plausible
hypotheses: strong interactions with the mequitazine included
in the cyclodextrin and/or strong interactions with the
complex formed.
The presence of this interaction agent primarily makes it
possible to improve the dissolution properties of the complex
in biological liquids, in particular water, and to possibly
increase the rate of inclusion of mequitazine in the
cyclodextrin.
The improvement of the physicochemical properties, in
particular in terms of dissolution of the system formed may
originate in:
- noncovalent interaction of the interaction agent with
mequitazine, the cyclodextrin, or both (complexation,
salification, etc.)/
- local pH variation in the dissolution medium,
- presence of an eutectic system,
- modification of the interface between the system and
its dissolution medium (surfactant effect, granulometric
change).
In the sense of the present invention, "dense fluid under
pressure" means any fluid used at a temperature or a pressure
greater than its critical value. Advantageously C02 may be
used pure or as mixture with an organic solvent classically
used by those skilled in the art.
In the sense of the present invention, "diffusion agent" means
any solvent that favors an interaction of mequitazine with a
cyclodextrin.
Advantageously, this diffusion agent is selected from among
the group consisting of the alcohols, ketones, ethers, esters,
and water, with or without a surfactant, and their mixtures.
In an even more advantageous way, water is selected.
In the sense of the present invention, "static mode" means a
reaction or a process in which all of the reagents are
simultaneously placed together and where the reaction is
allowed to progress. For example, in step (b) of the present
invention, into an autoclave are placed the substances of the
complex, water, and supercritical C02, and the reaction is
allowed to progress for several hours. The mass of the product
does not change during the reaction. On the contrary, in
dynamic mode, the reagents are supplied as the reaction or
production progresses. Often within the framework of dynamic
mode, there is circulation of a fluid. The mass of the product
changes during production.
In an advantageous way, molecular diffusion step (b) of the
method according to the present invention is carried out under
stirring.
In a particular embodiment of the invention, during step (a)
mequitazine, the interaction agent, and the cyclodextrin are
introduced in solid or liquid form into a receptacle into
which during step (b) is injected the dense fluid under
pressure and the diffusion agent in judiciously selected
proportions. Pressure and temperature conditions, as well as
the duration of treatment, are defined by any suitable method.
The diffusion agent can be added continuously or
discontinuously in a quantity ranging between 1 and 50% in
mass compared to the total mass of the mixture, preferably
between 10 and 25% in mass compared to total mass of the
mixture.
The time necessary for the molecular diffusion in step (b) is
determined by any suitable method. Step (b) may be repeated as
many times as desired to obtain a satisfactory rate of
dissolution. Advantageously, step (b) lasts between
approximately 1 and 16 hours, advantageously 2 hours.
The pressure and temperature conditions in step (b) are chosen
in a way to favor molecular diffusion. Advantageously the
pressure of the supercritical fluid lies between 0.5 MPa and
50 MPa, advantageously 15 MPa, and the temperature between 0
and 200 °C, advantageously 75 °C.
Advantageously step (b) of the process is implemented in a
closed reactor, in particular an autoclave.
The process can be implemented in batches or continuously. In
an advantageous way the process according to the present
invention is carried out in batches.
The mequitazine/cyclodextrin/interaction agent molar ratio can
be chosen in a way to ensure optimal inclusion of mequitazine
within the cyclodextrins. Thus, advantageously the
mequitazine/cyclodextrin molar ratio lies between 1/1 and
1/10, advantageously between 1/1 and 1/5, and in an
advantageous way between 1/2 and 1/3. In the same advantageous
way the mequitazine/interaction agent molar ratio lies between
1/1 and 1/10, advantageously between 1/1 and 1/5, and in an
advantageous way between 1/1 and 1/3.
Advantageously, step (b) of the process is implemented in a
closed reactor, possibly under stirring, supplied with the
dense fluid and the mequitazine solution, continuously if need
be.
The present invention relates moreover to a pharmaceutical
composition, intended to be administered by oral route, that
includes a complex according to the present invention, and
possibly a pharmaceutically acceptable excipient.
It concerns moreover a complex according to the present
invention or a pharmaceutical composition according to the
present invention for its use as a drug, advantageously
intended to treat allergies.
The following examples, given as indications, were carried out
with mequitazine in racemic form and/or D- or L- enantiomer
form, with the additional use of |3-cyclodextrin, water as a
diffusion agent, and arginine as an interaction agent.
COMPARATIVE EXAMPLE 1: Creation of mequitazine/(3-cyclodextrin
complexes.
2.5 grams of mequitazine in racemic or L- or D- form, 20.11
grams of (3-cyclodextrin, and 5.11 grams of water are mixed and
introduced into a 500 ml reactor. Carbon dioxide is then
introduced into the reactor under a pressure of 15 MPa and at
a temperature of 75 °C. The unit is maintained under these
operating conditions for 2 hours. The powder thus collected
after releasing the medium is placed in a drying oven at 60 °C
overnight.
The solubility and the rates of solubilization of complexed
mequitazine (D, L, or racemic) are measured as indicated above
in the "mequitazine solubilization test". The results are
collected in Table 1 and represented in Figure 1 below.
EXAMPLE 2: Creation of mequitazine/ft-cyclodextrin/arginine
complexes.
The procedure is identical to that of Example 1, only the
quantities of the reagents change. 2.5 grams of mequitazine in
racemic or L- or D- form, 20.11 grams of |3-cyclodextrin, 1.35
grams of arginine, and 5.63 grams of water are used.
The solubility and the rates of solubilization of complexed
mequitazine (D, L, or racemic) are measured as indicated above
in the "mequitazine solubilization test". The results are
collected in Table 1 and represented in Figure 1 below.
COMPARATIVE EXAMPLE: Solubility of racemic, L-, and Dmequitazine
taken separately and physical mixtures of
mequitazine/(3-cyclodextrin and mequitazine/ftcyclodextrin/
arginine.
Moreover, the rates of solubilization of the mequitazine
obtained thanks to the use of the complexes according to the
present invention are compared with the rates of
solubilization obtained with the simple
cyclodextrin/mequitazine mixture and optionally an interaction
agent, such a mixture is called a "physical mixture" and has
nothing in common with complexes.
Creation of a "physical mixture":
A "physical mixture" corresponds to the simple mixture of the
components but in a non-complexed form. It is thus a question
of using the molar ratios of mequitazine/cyclodextrin and
possibly arginine as interaction agent used to create the
complexes, and to carry out solubility tests on these
"physical mixtures".
Thus the superiority of the complexes according to the present
invention can be demonstrated, in particular compared to
simple physical mixtures which correspond, for example, to the
product described in patent application FR 2 742 053.
The solubility and the rates of solubilization of mequitazine
only or mequitazine in physical mixtures are measured as
indicated above in the "mequitazine solubilization test".
The solubilization results are collected in Table 1 and
represented in Figure 1 below.
14
Table 1: Rate of solubilization of mequitazine in the various
samples: mequitazine alone, in a simple physical mixture, or
in complex with cyclodextrin or cyclodextrin and arginine.
(Table Removed)
Figure 1 represents the rates of solubilization of mequitazine
for the various samples tested at 37 °C after 15 minutes of
stirring for a 2 g/1 solution of mequitazine.
Thus it can be noted that the complexes according to the
present invention allow a particularly increased mequitazine
solubility, to be specific at pH 9. Such a pH is particularly
interesting because it corresponds to intestinal pH. It can
also be noted that mequitazine alone has a very low solubility
at this pH.
A difference in solubility between racemic mequitazine and
when complexed with either enantiomer can also be noted. It
appears that in the complexed form the enantiomer complexes
have the best solubility.
It is also observed that the simple physical component
mixtures, even if they make it possible to increase the rate
of dissolution of mequitazine, do not make it possible to
obtain results as satisfactory as those obtained with the
complexes. Thus, with the complexes, the rate of dissolution
is increased by a factor of approximately 3. In the same way,
simple complexation without an interaction agent does not make
it possible to obtain results as satisfactory as those
obtained with the complexes according to the present
invention.

CLAIMS
1. A complex that includes mequitazine, a cyclodextrin, and
an interaction agent wherein the rate of solubilization in
water of complexed mequitazine, measured for a 2 g/1 mixture
of mequitazine in water at 35 °C after 15 minutes of stirring,
is greater than 50% at pH 9.
2. A complex according to claim 1, wherein mequitazine is in
the form of only one enantiomer D- or L- and wherein the rate
of solubilization in water of complexed mequitazine measured
for a 2 g/1 mixture of mequitazine in water at 35 °C after 15
minutes of stirring, is greater than 60% at pH 9,
advantageously greater than 70% at pH 9.
3. A complex according to claim 2, wherein mequitazine is in
the form of its L- enantiomer and wherein the rate of
solubilization in water of complexed mequitazine measured for
a 2 g/1 mixture of mequitazine in water at 35 °C after 15
minutes of stirring, is greater than 80% at pH 9.
4. A complex according to any of the preceding claims,
wherein the interaction agent is L-arginine.
5. A method of preparing a complex according to any of
claims 1 to 4 wherein it comprises the following successive
stages:
a) placing mequitazine in contact with a cyclodextrin and
an interaction agent;
b) implementing a molecular diffusion step by placing in
contact in static mode a dense fluid under pressure
with the mixture obtained in step (a) in the presence
of one or more diffusion agents;
c) recovering the mequitazine/cyclodextrin/ interaction
agent complex thus formed.
6. A process according to claim 5 wherein it includes an
additional step (d) of drying the complex, advantageously at a
temperature ranging between 60 and 80 °C.
7. A process according to claim 5 or claim 6 wherein the
dense fluid under pressure is carbon dioxide.
8. A process according to any of claims 5 to 7 wherein the
diffusion agent is selected from among the group comprising
the alcohols, ketones, ethers, esters, and water, with or
without surfactant agent, and their mixtures, advantageously
the selection is water.
9. A process according to any of claims 5 to 8 wherein
molecular diffusion step (b) is carried out under stirring.
10. A process according to any of claims 5 to 9 wherein the
diffusion agent is added continuously or discontinuously in a
quantity ranging between 1 and 25% in mass, preferably between
10 and 25% in mass.
11. A process according to any of claims 5 to 10 wherein the
mequitazine/cyclodextrin molar ratio lies between 1/1 and
1/10, advantageously between 1/1 and 1/5, in an advantageous
way between 1/2 and 1/3.
12. A process according to any of claims 5 to 11 wherein the
mequitazine/interaction agent molar ratio lies between 1/1 and
1/10, advantageously between 1/1 and 1/5, in an advantageous
way between 1/1 and 1/3.
13. A pharmaceutical composition, intended to be administered
by oral route, that includes a complex according to any of
claims 1 to 4.
14. A complex according to any of the claims 1 to 4 or a
pharmaceutical composition according to claim 13 for use as a
drug, advantageously intended to treat allergies.

Documents:

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Patent Number

270556

Indian Patent Application Number

2627/DELNP/2007

PG Journal Number

01/2016

Publication Date

01-Jan-2016

Grant Date

30-Dec-2015

Date of Filing

09-Apr-2007

Name of Patentee

PIERRE FABRE MEDICAMENT

Applicant Address

45, PLACE ABEL GANCE, F-92100 BOULOGNE-BILLANCOURT, FRANCE

Inventors:

#	Inventor's Name	Inventor's Address
1	FREISS, BERNARD	178 CHEMIN DE LA FOSSE, F-81100 CASTRES, FRANCE
2	LOCHARD, HUBERT	23, RUE MARCEL PAGNOL,F-81000 ALBI, FRANCE

PCT International Classification Number

A61K 47/78

PCT International Application Number

PCT/EP2005/055388

PCT International Filing date

2005-10-19

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	0411202	2004-10-21	France