Title of Invention

DIOXOANTHRACENE SULPHONATE DERIVATIVES

Abstract Compounds that may have anti-inflammatory activity have the general formula (I): Wherein R1, R2, R3 are each independently H or a C1-4 alkyl group or a C2-4 acyl group; R4 and R5 are each independently H or a group of formula -SO3R6, wherein R6 is H or a C1-4 alkyl group or a C2-4 acyl group; with the proviso that at least one of R4 and R5 is a group of formula -SO3R6, or a pharmaceutically acceptable salt thereof.
Full Text Dioxoanthracene sulphonate derivatives
The present invention relates to certain dioxoanthracene sulphonate
derivatives, to a process for the preparation thereof, and to the use of the
compound as a medicament, particularly in the therapy of conditions that are
influenced by pro-inflammatory cytokines of the IL-1 family, particularly
inflammatory and auto-immune diseases, for instance arthritic diseases.
Rhein, 4,5-dihydroxy-9,10-dioxo-2-anthracene carboxylic acid, and its
diacetylated derivative diacerein, are known for a number of pharmaceutical
applications. Particularly rhein and diacerein are known for use in the treatment
of arthritic diseases, in particular osteoarthritis and rheumatoid arthritis, for
instance as described in US 4,244,968, GB 1 578 452, EP 544 880 B1, EP 636
602 B1 and US 6,610,750, and psoriasis and associated conditions, as
described in EP 1 248 608 B1. Rhein and diacerein have also been described
for the treatment of various conditions, for instance inflammatory diseases,
auto-immune diseases, vascular diseases, pain relief, diabetic nephrosis.
The cytokines IL-1 (a, ß) and TNF-a are considered to play an essential role in
the mediation of the inflammatory process and cartilage degradation. IL-1 and
TNF-a are also considered to be implicated in the mediation of biological
responses to endotoxins and other infectious stimuli. An extensive review of
pro-inflammatory and anti-inflammatory cytokines is given by CADinarello, MD
et L.L.Moldawer.PhD in the primer for clinicians "Proinflammatory and Anti-
inflammatory Cytokines in Rheumatoid Arthritis", 2000, Amgen Inc. The
cytokines IL-1 and TNF-a have been implicated in the mechanism of a number
of inflammatory and auto-immune conditions such as osteoarthritis, rheumatoid
arthritis, psoriatic arthritis, psoriasis, Paget's disease, osteoporosis,
inflammatory bowl diseases including ulcerative colitis and Crohn's disease,
endometriosis, Wegener's granulomatosis, neurological dysfunctions such as
Alzheimer's disease and Parkinson's disease, myeloma, myeloid leukaemia,
bone metastasis, diabetic nephrosis, chronic heart disease, arthrosclerosis,
asthma.
Diacerein and its active metabolite rhein are known to inhibit the synthesis and
activity of pro-inflammatory catabolic cytokines of the interleukin-1 (IL-1) family,
particularly IL-1ß. Rhein and diacerein have been shown to inhibit expression
of IL-6, IL-8 and other cytokines such as tissue necrosis factor (TNF-a).
Inhibition of inflammatory cytokines IL-1 and TNF-a by rhein and diacerein is
described, for instance, in WO 02/058681, WO 01/051044, J. Martel-Pelletier
et al. Journal of Rheumatology, 1998, 25(4), 753-762, E. Douni et al. Arthritis
Res Ther, 2004, 6: R65-R72.
Chondrocytes from patients suffering from these conditions express high levels
of TNF-a and IL-1, compared to chondrocytes from healthy individuals, and this
specific mechanism of action of rhein as an IL-1 inhibitor is believed to explain,
at least in part, the effectiveness of rhein and diacerein in the treatment of
certain arthritic conditions, for instance, rheumatoid arthritis, osteoarthritis and
psoriatic arthritis.
The metabolite Aloe-emodin present in diacerein has, however, been shown to
have clastogenic effect in colon and kidney cells. Genotoxicity of Aloe-emodin,
tested by Comet assay, is reported, for instance, by S.O. Muller et al., Mutation
Research, 371, (1996), 165-173.
Further, rhein and diacerein have the drawback of being poorly soluble in
aqueous solution, making the preparation of pharmaceutical dosage forms,
from which the therapeutic agent is bioavailable, difficult. The poor solubility of
rhein and diacerein is a particular problem with respect to formulations for
parenteral administration.
Diacerein, and its active metabolite rhein, are known to have a tendency to
produce laxative effects in patients over long-term treatment. It is believed that
this laxative effect may be attributed, at least in part, to the very poor solubility
of rhein and diacerein.
There is an ongoing need to provide further compounds for the treatment or
therapy of conditions that are influenced or mediated by pro-inflammatory
cytokines of the IL-1 family, particularly inflammatory and auto-immune
diseases, including arthritic diseases.
It would further be advantageous to provide alternative compounds having
activity for the inhibition of pro-inflammatory cytokines of the IL-1 family, and
which allow to address certain drawbacks of rhein and/or diacerein.
It would be further advantageous to provide compound having improved activity
for the inhibition of pro-inflammatory cytokines of the IL-1 family.
There are now provided novel pharmaceutical compounds of the formula (I):
wherein R1, R2, R3 are each independently H or a C1-4 alkyl group or a C2-4 acyl
group;
R4 and R5 are each independently H or a group of formula -SO3R6, wherein R6
is H or a C1-4 alkyl group or a C2-4 acyl group;
with the proviso that at least one of R4 and R5 is a group of formula -SO3R6.
According to a particular embodiment of the present invention there is provided
a compound of the formula (I) wherein R1, R2, R3 and R4 are H, and R5 is
-SO3H (formula (III)).
It has unexpectedly been found by the inventors that compounds of the formula
(I) are capable of inhibiting production of pro-inflammatory cytokines of the IL-1
family. Compounds of formula (I) wherein R4 and/or R5 is -SO3H have also been
shown to exhibit advantageous solubility properties.
According to one aspect of the present invention there is provided a process for
the preparation of a compound of formula (I), which comprises treating the
corresponding compound of formula (II):

Wherein R1, R2 and R3 are each independently H, with sulphuric acid.
According to one aspect of the invention there is now provided a
pharmaceutical composition comprising a compound of formula (I) in
combination with suitable pharmaceutically acceptable excipients.
According to further aspects, the present invention relates to a compound of
formula (I) for use as a medicament for human or veterinary application, to a
compound of formula (I) for the treatment of conditions that are mediated or
influenced by cytokines of the IL-1 family, particularly for the treatment of
inflammatory or auto-immune diseases, to the use of a compound of formula (I)
for the preparation of a medicament for the treatment of conditions that are
mediated or influenced by cytokines of the IL-1 family, particularly inflammatory
or auto-immune diseases, and to a method for the treatment of a condition
mediated or influenced by cytokines of the IL-1 family, which comprises
administering to a subject a therapeutically effective amount of a compound of
formula (I).
Other objects and advantages of the present invention will be apparent from
the claims and the following detailed description, examples and accompanying
drawings.
Figures 1(a), 1(b) and 1(c) show the 1H-NMR spectra of a compound according
to the present invention;
Figure 2 shows the MS analysis of the same compound according to the
present invention;
Figure 3 is a graphical representation showing the effects of a compound
according to the present invention on the inhibition of IL-1ß cytokine production
in human chondrocytes; and
Figure 4 is a graphical representation showing the dose-dependent inhibition of
IL-1ß cytokine production in human chondrocytes by a compound according to
the present invention.
The present invention provides a compound of the formula (I):
Wherein R1, R2, R3 are each independently H or a C1-4 alkyl group or a C2-4 acyl
group;
R4 and R5 are each independently H or a group of formula -SO3R6, wherein R6
is H or a C1-4 alkyl group or a C2-4 acyl group;
with the proviso that at least one of R4 and R5 is a group of formula -SO3Re.
According to one embodiment of the invention R1 and R2 are independently
selected from H, a C1-4 alkyl group or a C1-4 acyl group; R3 is H, and R4 and R5
may be H or -SO3H, with the proviso that at least one of R4 and R5 is -SO3H. In
a preferred embodiment, R1 and R2 are either both H or both acetyl groups, R3
and R4 are both H, and R5 is -SO3H.
According to one embodiment of the invention R1, R2, R3 are H, and R4 and R5
are independently H or -SO3H, with the proviso that at least one of R4 and R5 is
-SO3H.
According to a preferred embodiment of the present invention there is provided
a compound of the formula (III) (6-sulfo-4,5-dihydroxy-9,10-dioxo-2-anthracene
carboxylic acid):
The compounds of the present invention may be in the form of a
pharmaceutically acceptable salt thereof. Particularly sodium, potassium or
ammonium salts are contemplated.
Compounds of formula (I) may be prepared by a process according to the
present invention, which comprises treating a compound of formula (II)

in which R1, R2 and R3 are H, with concentrated sulphuric acid to produce the
corresponding compound of formula (I), in the form of the sulphonic acid. In a
further step desired C1-4 alkyl group or a C2-4 acyl group can be selectively
substituted using conventional techniques. For instance, reaction with a C2-4
acyl halide, or corresponding acyl anhydride, to introduce the desired C2-4
acyloxy group, reaction with a C1-4 alcohol to form the corresponding ester, or
for instance reaction with diazomethane (CH2N2) to introduce C1 alkyl group or
with a C2-4 alkyl halide to introduce the corresponding C2-4 alkyl group.
Depending on the desired substitution, known protecting groups may be
introduced, where necessary, and cleaved using conventional processes.
Alternatively, sulphuric acid can be replaced with pyrosulphuric acid.
The reaction with sulphuric acid is preferably carried out at a temperature
between 60 and 120° C, preferably around 100°C.
The reaction time with the acid may vary, dependent for instance on the
reaction temperature, the acid used, the desired product (i.e. di- or mono-
sulphonic acid substitution) etc. As a general indication reaction times of
between 1 hour and 48 hours may be envisaged, for instance around 24 hours.
The progress of the reaction may advantageously be monitored, for example by
HPLC, and the reaction stopped at completion of the reaction to the desired di-
or mono- sulphonate substituted product.
The product may be isolated in the form of its corresponding salt, for instance
by addition of the corresponding metal halide (e.g. NaCI), or the corresponding
metal alkalizing agent (such as NaOH, KOH or NH3). Salts envisaged include
any pharmaceutically acceptable salt, such as, for instance, sodium, potassium
or ammonium.
The thus obtained compound of formula (I) may be purified using any suitable
conventional purification process, such as, for instance, preparative HPLC or
liquid-liquid partitioning.
Compounds of formula (I) according to the present invention exhibit activity in
the inhibition of pro-inflammatory cytokines of the IL-1 family.
In in-vitro studies in human chondrocytes, compounds of formula (I) have
unexpectedly been shown to exhibit improved inhibition of interleukin-1 (IL-1 (3),
compared to rhein.
Advantageously, compounds of formula (I) can allow to avoid the metabolite
aloe-emodin, present in diacerein.
In view of their activity in the inhibition of pro-inflammatory cytokines of the IL-1
family, compounds of the present invention are contemplated for the treatment
of conditions characterised by an abnormally high or increased level of IL-1.
The conditions that may be treated with compounds of the present invention
include inflammatory and auto-immune diseases. Conditions that may be
mentioned include rheumatoid arthritis, osteoarthritis, osteoporosis, psoriatic
arthritis, psoriaris, artherosclerosis, Paget's disease, chronic heart disease,
inflammatory bowl diseases including ulcerative colitis and Crohn's disease,
endometriosis, Wegener's granulomatosis, neurological dysfunctions such as
Alzheimer's disease and Parkinson's disease, myeloma, myeloid leukaemia,
bone metastasis, diabetic nephrosis, pneumonary emphysema, asthma.
Accordingly, one aspect of the present invention relates to a method of treating
conditions characterised by increased levels of IL-1, as compared to healthy
individuals, which comprises administering to a subject an effective amount of a
compound according to the present invention or a pharmaceutically acceptable
salt thereof. The conditions are preferably inflammatory diseases or auto-
immune diseases. Particularly the conditions to be treated include inflammatory
diseases of the joints in particular osteoarthritis or rheumatoid arthritis.
Psoriatic arthritis and psoriasis may also be particularly mentioned.
It is likely that the compounds of the present invention will be of clinical utility in
the wide range of inflammatory and auto-immune diseases described above,
due also to their improved physical properties compared with rhein.
According to one aspect of the invention there is provided a pharmaceutical
composition comprising the compound of formula (I) in combination with
suitable pharmaceutically acceptable excipients. Pharmaceutical compositions
according to the present invention may be for human or veterinary use.
The pharmaceutical compositions according to the present invention may have
a formulation suitable for administration by any route, including, for example,
oral, intramuscular, intravenous, subcutaneous, rectal, topical, transcutaneous,
intranasal, intrarticular, sublingual and intraperitoneal administration.
Formulations for oral administration may include, for instance, tablets, hard or
soft gelatin capsules, lozenges, aqueous or oily suspensions, dispersible
powders or granules for reconstitution, syrups or emulsions.
Formulations for parenteral administration may be in any suitable
pharmaceutical form, such as in the form of a sterile injectable aqueous
buffered solution or suspension, as a sterile injectable solution or suspension
in any other non-toxic parenterally acceptable diluent or solvent, or in a freeze-
dried form for reconstitution at the time of use.
The compositions of the present invention may be also be provided in
formulations for topical administration, for instance in the form of a cream, gel,
ointment or emulsion in an aqueous or oily carrier.
Compounds of formula (I) according to the present invention are expected to
show better solubility in water than rhein or diacerein due to the presence of
the sulphonate group. For instance, compounds of formula (I) according to the
present invention wherein R1, R2, R3 are H and R4 and R5 are independently or
both SO3H, have been shown to exhibit particularly good solubility in aqueous
solution. For example, the compound of formula (III) has a solubility in water of
1.2 mg/ml while rhein and diacerein are practically insoluble in water.
The good solubility properties of the compounds of the present invention allows
the compounds to be advantageously administered by parenteral routes, e.g.
by injection or infusion, particularly as intraarticular, intramuscular, intravenous
or subcutaneous injection or infusion.
The pharmaceutical compositions may be prepared according to methods
known in the art, using suitable known pharmaceutically excipients and/or
additives.
Any suitable conventional pharmaceutically acceptable excipients are
contemplated, for example diluents, binders, surfactants, lubricants,
suspending agents, emulsifiers, buffers anticaking agents, aqueous or oily
carriers, disintegrating agents, preserving agents, flavouring agents,
sweetening agents, colouring agents, in accordance with the selected route of
administration.
Suitable dosage regimes will vary dependent, amongst other things, on factors
such as the therapeutic application, the severity of the condition and with
respect to the patient to be treated. Typical daily dosage amounts may vary in
the order of from about 0.05 mg to about 150 mg per kg of patient bodyweight
per day. In general terms a daily dosage of from about 10mg to 500mg per day,
such as between about 10mg and about 250mg per day may be envisaged.
The amount of active ingredient in a unit dosage from will depend on the above
factors and also on the chosen route of administration, and will generally be in
the region of 1 mg to 500 mg of active ingredient per unit dosage form.
The invention is further illustrated by the following-non limiting examples.
EXAMPLES
Example 1
Preparation of 6-sulfo-4,5-dihydroxy-9,10-dioxo-2-anthracene carboxylic acid
Rhein (1g) produced by the deacetylation of pure diacerein, having a purity
more than 99%, was dissolved in concentrated sulphuric acid (100 ml). The
solution was heated at 100° C and stirred for 24 hours. Progress of the reaction
was followed in real time using HPLC to completion of the reaction. The
reaction mixture was then allowed to cool and poured into 21 water with stirring.
The resultant solution was then stored over the night at 4°C. The unreacted
rhein salting material was eliminated by centrifuge. The compound 6-sulfo-4,5-
dihydroxy-9,10-dioxo-2-anthracene carboxylic acid was precipitated as its
sodium salt by the addition of 110 g of sodium chloride. The resulting
suspension was cooled at 4°C for one hour, then centrifuged to separate out
the solid product and dried under vacuum. 2.32 g of product was obtained.
Elimination of salts:
The product obtained above was added to water (115 ml) with mixing at 4°C for
30 minutes. The suspension was then centrifuged and decanted to eliminate
the supernatant with the residual salts. This operation was repeated seven
times until a constant conductivity (around 330 µS/cm), measured with a
conductivity meter (Radiometer CDM 206). The residue after centrifuging was
then dried under vacuum to obtain 480 mg of product, with a purity of 95.6% as
determined by HPLC.
Example 2
Characterization
1H-NMR analysis:
1H-NMR spectaim of the product obtained in example 1 was carried out in
dimethyl sulphoxide (DMSO) using a Bruker® spectrometer at 400 MHz. The
spectra obtained, shown in figures 1(a) to 1(c), shows concordance with the
product 6-sulfo-4,5-dihydroxy-9,10-dioxo-2-anthracene carboxylic acid.
The 1H-NMR spectra indicates the presence of only four aromatic protons, two
in the meta position and two in ortho positions. Showing that the sulphonic acid
substitution has occurred in the ring which previously had only a hydroxyl
substituent. The chemical displacements (shifts), compared to caculated
chemical displacements on the basis of increments, show the substitution of the
sulphonic acid group to be in the ortho position.
MS analysis:
Mass spectroscopy carried out on the product of example 1 with an Agilent
1100 LC-MS Spectrometer, with ionisation at atmospheric pressure in negative
eletro-spray mode. The spectrum obtained, shown in figure 2, shows a peak at
364, and thus concords with the product 6-sulfo-4,5-dihydroxy-9,10-dioxo-2-
anthracene carboxylic acid, formula (III).
Example 3
Preparation of 6-sulfo-4,5-dihydroxy-9,10-dioxo-2-anthracene carboxylic acid
sodium salt
Rhein (1g) produced by the deacetylation of pure diacerein, having a purity
more than 99%, was dissolved in concentrated sulphuric acid (100 ml). The
solution was heated at 100° C and stirred for 24 hours. Progress of the reaction
was followed in real time using HPLC to completion of the reaction. The
reaction mixture was then allowed to cool and poured into 21 water with stirring.
The resultant solution was then stored over the night at 4°C. The unreacted
rhein salting material was eliminated by centrifuge. The pH of the surnatant
was adjusted to 7.0 with NaOH 1M. The product 6-sulfo-4,5-dihydroxy-9,10-
dioxo-2-anthracene carboxylic acid, in the form of its sodium salt, was then
isolated and purified from the solution by preparative HPLC using a reversed
phase C18 silica column and methanol/water/H3PO4 eluent. 1g of product was
isolated and characterised as 6-sulfo-4,5-dihydroxy-9,10-dioxo-2-anthracene
carboxylic acid sodium salt by NMR and MS as in example 2.
Example 4
In vitro studies on IL-1ß inhibition in human chondrocytes
The activity of the compound of example 1, and of rhein in inhibiting the
lipopolysaccharide (LPS) stimulated production of IL-1ß cytokine by human
normal and osteoarthritic (OA) chondrocytes was studied.
Materials and methods:
Human cartilage was obtained during orthopaedic surgery for total hip
prosthesis due to traumatic fracture in normal subjects or OA patients. Patients
with OA were selected on the basis of the following criteria (1) bi-lateral OA, (2)
diagnoses of moderate OA (grade l-lll, Kellgren-Laurence), supported by
radiology and pathology.
A suspension of isolated chondrocytes was prepared from cartilage specimens
obtained from four OA patient and nine normal subjects. Specimens were
obtained and maintained under aseptic conditions. The cartilage was cut into
small fragments and incubated with 1 mg/ml clostridial collagenase in
carbonate/bicarbonate buffer for 48 hours at 37°C. Once separated from the
cartilage matrix, chondrocytes were centrifuged at 1500 RPM for five minutes.
The separated chondrocytes, suspended in culture medium (DMEM
supplemented with 10% SCF) were used for the experiment. Cell viability was
evaluated by Trypan blue exclusion.
In vitro stimulation of chondrocytes with bacterial endotoxin (LPS) for the
production of IL-1ß was carried out as follows:
Aliquots of 1 x 106 cells/ml in culture medium were seeded in 15 ml Falcon
tubes and maintained under agitation on a gyratory shaker (100 RPM).
Chondrocytes were cultured for 48 hours in the presence of MPS (10 µg/ml)
with 20 mg/ml rhein, or increasing concentrations (1, 5,10, 20 and 30 µg/ml) of
the test compound (compound of Example 1). For the samples with rhein the
solution was subjected to five minutes sonication in order to minimize solubility
problems related to the hydrophobic nature of rhein. This problem was not
present for the solutions of the test compound due to its good solubility.
IL-1ß production by chondrocytes was assayed in the culture medium in the
various sample cultures by an ELISA kit.
Figure 3 shows the results obtained with rhein and the compound of Example 1
on IL-1ß production in LPS-stimulated normal and OA chondrocytes, as
evaluated by ELISA. Figure 4 shows the dose-dependent inhibition of IL-1ß
production of normal chondrocytes by the test compound (compound of
Example 1). The results illustrated in figure 3 show the compound of the
present invention to exhibit significantly increased IL-1ß inhibition activity
compared with rhein. Figure 4 shows the compound according to the invention
to provide significant inhibition of IL-1ß production, with maximum inhibition
between 10 and 20 mg/ml.
Claims
1. A compound of the formula (I):

Wherein R1, R2, R3 are each independently H or a C1-4 alkyl group or a C2-4 acyl
group;
R4 and R5 are each independently H or a group of formula -SO3R6, wherein R6
is H or a C1-4 alkyl group or a C2-4 acyl group;
with the proviso that at least one of R4 and R5 is a group of formula -SO3R6,
or a pharmaceutically acceptable salt thereof.
2. A compound according to claim 1, wherein R1, R2 are independently H or
a C1-4 alkyl group or a C2-4 acyl group, R3 and R4 are H, and R5 is -SO3H.
3. A compound according to claim 1 or 2 having the formula (III):
4. A compound according to any one of claims 1 to 3 for use as
medicament.
5. A compound according to any one of claims 1 to 3 for the treatment of a
condition that is mediated or influenced by pro-inflammatory cytokines of the IL-
1 family.
6. A compound according to any one of claims 1 to 3 for use as
medicament for the treatment of an inflammatory or auto-immune condition.
7. A compound according to any one of claims 1 to 3 for the treatment of a
condition selected from rheumatoid arthritis, osteoarthritis, osteoporosis,
psoriatic arthritis, psoriaris, artherosclerosis, Paget's disease, chronic heart
disease, inflammatory bowl diseases including ulcerative colitis and Crohn's
disease, endometriosis, Wegener's granulomatosis, neurological dysfunctions
such as Alzheimer's disease and Parkinson's disease, myeloma, myeloid
leukaemia, bone metastasis, diabetic nephrosis, pneumonary emphysema,
asthma.
8. A compound according to claim 7 where the condition is selected from
osteoarthritis, rheumatoid arthritis, psoriatic arthritis and psoriasis.
9. A pharmaceutical composition comprising a compound according to any
one of claims 1 to 3, or a pharmaceutical^ acceptable salt thereof, as an active
ingredient.
10. A pharmaceutical composition according to claim 9, wherein the
composition is for parenteral administration.
11. A pharmaceutical composition according to claim 9, wherein the
composition is for oral administration.
12. A pharmaceutical composition according to claim 9, wherein the
composition is for topical administration.
13. Method for the treatment of a condition mediated or influenced by pro-
inflammatory cytokines of the IL-1 family, which comprises administering to a
subject a therapeutically effective amount of a compound according to any one
of claims 1 to 3, or a pharmaceutically acceptable salt thereof.
14. Method for the treatment of an inflammatory or auto-immune disease
which comprises administering to a subject a therapeutically effective amount
of a compound according to any one of claims 1 to 3, or a pharmaceutically
acceptable salt thereof.
15. Method according to claim 13 wherein the disease is selected from
osteoarthritis, rheumatoid arthritis, psoriatic arthritis and psoriasis.
16. Use of a compound according to any one of claims 1 to 3 for the
manufacture of a medicament for the treatment of conditions that are mediated
or influenced by pro-inflammatory cytokines of the IL-1 family.
17. Method for the preparation of a compound of formula (I):
Wherein R1, R2, R3 are each independently H or a C1-4 alkyl group or a C2-4 acyl
group;
R4 and R5 are each independently H or a group of formula -SO3R6, wherein R6
is H or a C1-4 alkyl group or a C2-4 acyl group;
with the proviso that at least one of R4 and R5 is a group of formula -SO3R6
or a pharmaceutically acceptable salt thereof,
comprising treating the compound of formula (II)
wherein R1, R2, R3 are H, with concentrated sulphuric acid.

Compounds that may have
anti-inflammatory activity have the general
formula (I): Wherein R1, R2, R3 are each
independently H or a C1-4 alkyl group or a C2-4
acyl group; R4 and R5 are each independently H
or a group of formula -SO3R6, wherein R6 is H
or a C1-4 alkyl group or a C2-4 acyl group; with
the proviso that at least one of R4 and R5 is a
group of formula -SO3R6, or a pharmaceutically
acceptable salt thereof.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=HZ1fFHzFqksBzsvO0nHgng==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 279770
Indian Patent Application Number 1794/KOLNP/2010
PG Journal Number 05/2017
Publication Date 03-Feb-2017
Grant Date 30-Jan-2017
Date of Filing 18-May-2010
Name of Patentee LABORATOIRE MEDIDOM S.A.
Applicant Address ENETRIEDERSTRASSE 44, CH-6060 SARNEN, SWITZERLAND
Inventors:
# Inventor's Name Inventor's Address
1 CARLINO, STEFANO RUE PRÉ DU PONT 21, CH-1868 COLLOMBEY, SWITZERLAND
2 DI NAPOLI, ALESSANDRO CHEMIN DU VENT-DEBOUT 18, CH-1245 COLLONGE-BELLERIVE, SWITZERLAND
PCT International Classification Number C07C 317/46
PCT International Application Number PCT/IB2008/054777
PCT International Filing date 2008-11-14
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 07022268.2 2007-11-16 EUROPEAN UNION