PHARMACEUTICAL COMPOSITION CONTAINING A TRYPTOPHAN DERIVATIVE

Abstract

Pharmaceutical compositions containing a compound of formula (I)

##STR00001##

wherein the radicals denote e.g.: R.sup.1 is hydrogen or C.sub.1-C.sub.8-alkyl; R.sup.2 is hydrogen or C.sub.1-C.sub.8-alkyl; R.sup.3 is hydrogen or C.sub.1-C.sub.8-alkyl; R.sup.4 is OH; R.sup.5 is hydrogen,
and a pharmaceutically acceptable cyclodextrin derivative can be used for the preparation of ophthalmic formulations.

Claims

1. Pharmaceutical composition comprising at least one compound of formula (I) ##STR00010## wherein the radicals denote: R.sup.1 is hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.3-C.sub.8-cycloalkyl, C.sub.6-C.sub.14-aryl, carboxy or C-thiocarb; in particular hydrogen or C.sub.1-C.sub.3-alkyl, R.sup.2 is hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.3-C.sub.8-cycloalkyl, C.sub.6-C.sub.14-aryl, carboxy or C-thiocarb; in particular hydrogen or C.sub.1-C.sub.3-alkyl, R.sup.3 is hydrogen or C.sub.1-C.sub.8-alkyl, in particular methyl, R.sup.4 is OH or OC.sub.1-C.sub.8-alkyl, in particular OH; R.sup.5 is hydrogen or C.sub.1-C.sub.8-alkyl, in particular hydrogen; and/or a pharmaceutically acceptable salt thereof, and/or a stereoisomeric form or derivative thereof, and at least one pharmaceutically acceptable cyclodextrin derivative (C) and optionally further components (F).

2. Pharmaceutical composition according to claim 1, wherein the composition contains at least one compound of formula (I) in which the radicals denote: R.sup.1 is hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.3-C.sub.8-cycloalkyl or C.sub.6-C.sub.14-aryl, R.sup.2 is hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.3-C.sub.8-cycloalkyl or C.sub.6-C.sub.14-aryl, R.sup.3 is hydrogen or C.sub.1-C.sub.8-alkyl, R.sup.4 is OH or OC.sub.1-C.sub.8-alkyl, R.sup.5 is hydrogen or C.sub.1-C.sub.8-alkyl, in particular hydrogen, and/or a pharmaceutically acceptable salt thereof, and comprises at least one further component (F).

3. Pharmaceutical composition according to claim 1, wherein the composition contains a compound of formula (I) wherein R.sup.1 is hydrogen or C.sub.1-C.sub.3-alkyl, R.sup.2 is hydrogen or C.sub.1-C.sub.3-alkyl, R.sup.3 is hydrogen or methyl, R.sup.4 is OH, R.sup.5 is hydrogen or C.sub.1-C.sub.8-alkyl, in particular hydrogen, and/or a pharmaceutically acceptable salt thereof, and comprises the solvent water and optionally further components (F).

4. Pharmaceutical composition according to claim 1, wherein the composition contains a compound of formula (I) wherein R.sup.1 and R.sup.2 are hydrogen, R.sup.3 is methyl, R.sup.4 is OH and R.sup.5 is hydrogen, and/or a pharmaceutically acceptable salt thereof, and comprises the solvent water and optionally further components (F).

5. Pharmaceutical composition according to claim 1, wherein the composition contains the R-enantiomer of the compound of formula (A) ##STR00011## and/or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable cyclodextrin derivative (C) and optionally a further active ingredient and/or further components (F).

6. Pharmaceutical composition according to claim 1, wherein the cyclodextrin compound (C) is selected from the group consisting of: alpha-cyclodextrin, beta-cyclodextrin, randomly alkylated beta-cyclodextrin, 2-O-methyl-beta-cyclodextrin, heptakis-(2,6-di-0-methyl)-beta-cyclodextrin (dimethyl-beta-cyclo-dextrin), acetylated dimethyl-beta-cyclodextrin, heptakis-(2,3,6-tri-0-methyl)-beta-cyclodextrin(trimethyl-beta-cyclodextrin, 2-hydroxypropyl-beta-cyclo-dextrin, sulfo-alkylether-beta-cyclodextrin, sulfobutylether-beta-cyclodextrin, O-carboxymethyl-O-ethyl-beta-cyclodextrin, glucuronyl-glucosyl-beta-cyclodextrin, glucosyl-beta-cyclo-dextrin, maltosyl-beta-cyclodextrin, beta-cyclodextrin sulphate, beta-cyclodextrin phosphate, gamma-cyclodextrin, 2-hydroxypropyl-gamma-cyclo-dextrin, sulfoalkylether-beta-cyclodextrin and sulfobutylether-beta-cyclodextrin.

7. Pharmaceutical composition according to claim 1, wherein the compound of formula (I) has the R-configuration and the cyclodextrin compound (C) is selected from hydroxyalkyl-substituted beta-cyclodextrins.

8. Pharmaceutical composition according to claim 1, wherein the molar ratio of the compound of formula (I) and the cyclodextrin compound (C) is in the range from 0.1:1 to 1:20.

9. Pharmaceutical composition according to claim 1, wherein the composition is an aqueous liquid composition comprising at least 70% by weight of water and wherein the concentration of the compound of formula (I) is in the range from 1 mg/ml to 50 mg/ml.

10. Pharmaceutical composition according to claim 1, wherein the composition is an aqueous liquid composition comprising as further component (F) a metal-containing preservative, in particular the preservative thiomersal.

11. A method of treating a disorder or a disease of the central nervous system, the method comprising administering to a subject in need thereof a pharmaceutical composition according to claim 1.

12. A method of treating an ophthalmic disorder or disease, the method comprising administering to a subject in need thereof a pharmaceutical composition according to claim 1.

13. Process for preparation of a pharmaceutical composition comprising the steps of mixing together at least one compound of formula (I) ##STR00012## wherein the radicals denote: R.sup.1 is hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.3-C.sub.8-cycloalkyl, C.sub.6-C.sub.14-aryl, carboxy or C-thiocarb; in particular hydrogen or C.sub.1-C.sub.3-alkyl, R.sup.2 is hydrogen, C.sub.1-C.sub.8-alkyl, C.sub.3-C.sub.8-cycloalkyl, C.sub.6-C.sub.14-aryl, carboxy or C-thiocarb; in particular hydrogen or C.sub.1-C.sub.3-alkyl, R.sup.3 is hydrogen or C.sub.1-C.sub.8-alkyl, in particular methyl, R.sup.4 is OH or OC.sub.1-C.sub.8-alkyl, in particular OH, R.sup.5 is hydrogen or C.sub.1-C.sub.8-alkyl, in particular hydrogen; and/or a pharmaceutically acceptable salt thereof, and/or a stereoisomeric form or derivative thereof, and at least one pharmaceutically acceptable cyclodextrin derivative (C) and optionally further components (F).

14. A pharmaceutical composition for use in the treatment of ophthalmic diseases, the composition comprising a cyclodextrin compound (C), in particular a hydroxyalkyl-substituted beta-cyclodextrin.

15. Pharmaceutical composition according to claim 14, further comprising a metal-containing preservative, in particular of thiomersal, wherein the pharmaceutical composition comprises a hydrophilic pharmaceutical agent, and wherein the concentration of the cyclodextrin compound (C) in the pharmaceutical composition is at least 10 mg/ml.

Description

EXAMPLE 1

[0154] Five pharmaceutical compositions were prepared using the compound (A), which has the chemical name 2-[2-Amino-3-(1H-indol-3-yl)-propionylamino]-2-methyl-propionic acid

##STR00009##

[0155] This compound (A) and its two enantiomers (R and S) were all prepared by classical chemical synthesis. The compound, and in particular its R-enantiomer, was tested in various compositions for CNS-applications and for ophthalmic uses.

[0156] In the following tests, the R-enantiomer of compound (A) was used. [0157] The compound (A) showed an aqueous solubility, at pH 7.2, of about 14 mg/ml. [0158] The compound (A) showed an aqueous solubility, at pH 7, of about 10 mg/ml. [0159] The compound (A) showed an aqueous solubility, at pH 6, of about 10 mg/ml. [0160] The compound (A) showed an aqueous solubility, at pH 4.6, of about 14 mg/ml.

[0161] At acidic conditions, the solubility of the compound (A) is higher.

[0162] At alkaline pH-values, the solubility of the compound (A) is also better.

[0163] The solubility of the R-enantiomer of compound (A) was determined as a function of the pH-value by using UV-spectroscopy to quantify the concentration of the compound in a series of aqueous media. It was found that from pH 4.5 to 7 the solubility is particularly low.

[0164] The octanol/water partition coefficient log P of the compounds of the invention can be determined by accepted standard methods known to the person skilled in the art, such as OECD (1995), Test No. 107: Partition Coefficient (n-octanol/water): Shake Flask Method, OECD Guidelines for the Testing of Chemicals, Section 1: Physical-Chemical properties, OECD Publishing. doi: 10.1787/9789264069626-en.

[0165] The log P value may be determined according to the draft OECD guideline OECD (2000), OECD Draft guideline for the Testing of Chemicals: 122 Partition Coefficient (n-Octanol/Water): pH-Metric Method for Ionisable Substances. For Example, log P of compound (A) was investigated using OECD (2000) OECD Draft guideline for the Testing of Chemicals: 122. The sample was titrated in two triple titrations from pH 1.9 to pH 10.9 at concentrations of 1.3 to 1.9 mM in various ratios of octanol/water. The apparent sample pKas in octanol/water were found to have no measurable shift from their aqueous values, hence the sample log P is lower than 1.

EXAMPLE 2

[0166] The following compositions I to V were prepared as solutions with a pH-value of about 7:

TABLE-US-00001 Composition I Composition II [mg/g] [mg/g] Compound (A) 8.0 8.0 Glycerol 28 28 Carbopol 974 P 1.3 1.6 Trometamol 1.0 1.2 Water ad 1000 ad 1000

TABLE-US-00002 Composition III Composition IV [mg/ml] [mg/ml] Compound (A) 30 30 Kleptose 160 160 Disodium hydrogen 4.15 4.15 phosphate Sodium dihydrogen 0.29 0.29 phosphate Sodium chloride 2.0 2.0 Methocel E4M 5.0 Water Qsp qsp
Composition V [mg/g]

TABLE-US-00003 Compound (A) 30 Kleptose 160 Glycerol (99%) 5.0 Gelrite 2.0 1M NaOH 0.015 mL; water qsp Water ad 1000

[0167] As it easily can be seen, compositions I and II (gel) contain 8.0 mg of compound (A) per ml of the composition. Composition I and II do not contain a cyclodextrin derivative (C).

[0168] The compositions III, IV and V contain 30 mg of compound (A) per ml of the composition. All three compositions III (solution), IV (gel) and V (in situ gel) also contain a considerable amount of a cyclodextrin derivative (C). Various ratios of compound of formula (I) to cyclodextrine derivative (C) were tested.

EXAMPLE 3

[0169] In the following table the major components of the pharmaceutical compositions tested are described in more detail:

TABLE-US-00004 Excipient Manufacturer/Supplier Kleptose HPB Roquette; Hydroxypropyl-beta-cyclodextrin Glycerol 99% Merck KGaA Gelzan CM Sigma Inc. (USA), Gellan Gum Carbomer 974 P Noveon, Carboxymethyl cellulose-Na Methocel E4M Colorcon, Methylhydroxy-propyl-cellulose Benzalkonium chloride Euro OTC solution 50% Kollidon 90 F BASF, Polyvinylpyrrolidone Trometamol Merck KGaA, Tris(hydroxymethyl)- aminomethan

[0170] The water used was water for injection.

[0171] The following properties were found for the pharmaceutical compositions I to V:

TABLE-US-00005 Compound A Osmolality Viscosity Composition [mg/mL] pH [mosmol/kg] [mPa*s] Composition I 8.0 6.4 315 40.8 Composition II 8.0 6.4 310 192.3 Composition III 30.0 6.9 305 1.5 Composition IV 30.0 6.9 320 18.1 Composition V 30.0 7.1 215 71.3

[0172] The five pharmaceutical compositions I to V, all containing the active ingredient (A), were applied to the eyes of test animals (dark agouti rats (pigmented) and to albino rats).

[0173] At different points of time after the administration of the compositions into the eye a micro-dissection of the eye of the animal was performed. Tissue samples were collected and a chemical dissolution and analysis was made for different compartments of the eye of the test animals.

[0174] With all five pharmaceutical compositions I to V, a significant amount of compound of formula (A) was delivered to the retina of the test animals. The evaluation of the results obtained from the Retina, the Vitreous, the Choroid and the Plasma of the test animals showed that the amounts of the compound (A) in the various compartments of the eye were significantly higher, when the compositions III, IV and V were used than when the pharmaceutical compositions I and II were applied.

[0175] For example, the amounts of compound (A) in the Retina of dark agouti rats was more than three times higher when composition III was applied (or when composition V was applied) than by applying compositions I or II to the eye of the test animal.

[0176] Therefore, a much better treatment of glaucoma can be achieved with compositions III to V than with compositions I and II.

EXAMPLE 4

[0177] For further pharmacological testing, three additional pharmaceutical compositions VI, VII and VIII were prepared by using the following components:

TABLE-US-00006 Composition VI Composition VII [mg/ml] [mg/ml] Compound (A) 20 20 Kleptose 160 160 Citric acid anhydrous 1.30 1.30 Sodium citrate dehydrate 7.70 7.70 Methocel E4M 5.0 Water qsp qsp

TABLE-US-00007 Composition VIII [mg/ml] Compound (A) 20 Kleptose 160 Glycerol 5.0 Gelrite 2.0 1M NaOH Water qsp

[0178] The pharmaceutical compositions VI (solution), VII (gel) and VIII (in situ gel) can be characterized by the following characteristics:

TABLE-US-00008 Compound A Osmolality Formulation [mg/mL] pH [mosmol/kg] Composition VI 20.0 5.7 288 Composition VII 20.0 5.7 266 Composition VIII 20.0 5.7 245

[0179] All three compositions VI, VII and VIII were tested in test animals (rats as described above). For all three compositions, significant amounts of compound (A) were delivered to the retina of the animals. The ratio of compound of formula (I) to cyclodextrine derivative (C) was 1:8. Even by using smaller concentrations of the active ingredient (A) in compositions VI, VII and VIII, and by using the preferred pH-value range of 5.6 to 6.2, very good test data were obtained.

EXAMPLE 5

[0180] For application to the human eye, the following ophthalmic composition IX was prepared:

TABLE-US-00009 Composition IX [mg/ml] Compound (A) 20 Kleptose 110 Citric acid anhydrous 0.80 Sodium citrate dehydrate 10.6 Methocel E4M 5.0 Sodium chloride 1.5 Water Qsp

[0181] This composition had a viscosity of 32 mPas (using a cone-plate rheometer, C60/1).

[0182] The release rate of compound (A) from this composition was tested in a Franz cell study (Supor-200 membrane). After 60 minutes, already 60% of the active compound were released.

[0183] An additional Composition IXa was prepared and tested comprising:

TABLE-US-00010 Composition IXa [mg/ml] Compound (A) 20 Kleptose 110 Citric acid anhydrous 0.80 Sodium citrate dehydrate 10.6 Methocel E4M 5.0 Glycerol 1.5 Water Qsp

EXAMPLE 6

[0184] In addition, the stability of the aqueous compositions VI to VIII at various temperatures (5 C., 25 C. and 40 C.) was investigated. Even after four weeks of storage, the compositions VI to VIII containing compound (A) only showed moderate degradation.

EXAMPLE 7

[0185] For further stability testing, the following compositions were prepared: [0186] a) 10 mg compound (A) per ml, with 0.1 mg sodium benzoate per ml; [0187] b) 10 mg compound (A) per ml, with 0.2 mg sodium benzoate per ml; [0188] c) 100 mg compound (A) per ml, with 0.1 mg sodium benzoate per ml; [0189] d) 100 mg compound (A) per ml, with 0.2 mg sodium benzoate per ml; [0190] e) 10 mg compound (A) per ml, with 0.1 mg sodium benzoate per ml and 10% (v/v) of propylene glycol; [0191] f) 10 mg compound (A) per ml, with 0.2 mg sodium benzoate per ml and 10% (v/v) of propylene glycol.

[0192] For all compositions, the compound (A) was dissolved in citric acid solution and completed to the required volume with citric buffer to a pH-value of 3.

[0193] Then, the preservatives were added. The six solutions were first tested for one week at room temperature.

[0194] None of the formulations showed any change after one week at room temperature, the optical appearance, the pH-value and the odor remained unchanged. Then they were stored for several weeks at temperatures of 25 C. with 60% humidity and at 5 C. The compositions with 10 mg compound (A) were stable for several months.

EXAMPLE 8

[0195] In the further series of tests, the compatibility of the compound (A) with other typical ophthalmic excipients was investigated. It was found that compound (A) in aqueous solutions at pH 5.5 showed no incompatibilities with many further components (F), such as hypromellose, carbomer, Gellan gum and various preservatives.

EXAMPLE 9

[0196] In a male Dark Aguti rat model, glaucoma is produced by injection of hypertonic saline into episcleral veins of one eye to induce increased ophthalmic pressure (chronic ophthalmic hypertension), while the opposite eye serves as a control. In treatment groups, various doses of compound (A) of the instant invention are injected intravitreally (in 50 l volume) at the time of glaucoma induction and in some groups the administration continues for following 7 days to see whether such extended treatment results in increased efficacy.

[0197] The extent of retinal ganglion cell (RGC) apoptosis at 3 weeks and 6 weeks after chronic ophthalmic hypertension (OHT) induction is assessed in each animal by dynamic confocal scanning laser ophthalmoscopy and fluorescent-labeled Annexin V.

[0198] Animals are sacrificed after 3 and 6 weeks and their eyes are enucleated and fixed in 4% para-formaldehyde overnight. Afterwards, retinas are separated for assessing apoptosis related changes, for example visualized with FITC Annexin V kit (BD Biosciences, Franklin Laker (USA).

[0199] In animals treated with low doses of compound (A), there is a strong decrease in RGC apoptosis compared to animals treated with the vehicle only. This shows that compound (A) is useful for the treatment of glaucoma.

[0200] The equilibrium solubility of compound (A) was tested in a citrate buffer saline at pH6 in presence of different cyclodextrins by the shake flask method.

[0201] The beta-cyclodextrins HPBCD and MBCD showed the best solubility improvement of the tested cyclodextrin derivatives.

TABLE-US-00011 Solubility of compound (A) [mg/mL] 110 mg/ml HPBCD (Kleptose HPB, Roquette) 27.9 110 mg/ml HPGCD (Cavasol W8 HP Pharma, 16.2 ISP) 110 mg/ml MBCD (Kleptose Crysmeb, 28.7 Roquette) 100 mg/ml ACD (-Cyclodextrin, Fluka) 12.7

[0202] All these compositions can advantageously be used for the treatment of the various ophthalmic diseases described above.

EXAMPLE 10

[0203] In male Dark Aguti rats, an aqueous formulation comprising 20 mg/mL of Compound (A) and 160 mg/mL Kleptose was applied (one time) to one eye, while the opposite eye served as a control.

[0204] In other male Dark Aguti rats, an aqueous formulation comprising 8 mg/mL of Compound (A) but containing no Kleptose (cyclodextrin) was applied (one time) to one eye, while the opposite eye served as a control. In the treatment groups, the formulations comprising compound (A) were injected intra-vitreally (in 10 l volume instillation) and the concentrations of compound (A) were measured in the retina of the animals (after 5 minutes). The mean concentrations of compound (A) are as follows: [0205] Formulation with Compound A 0.005% of dose applied, [0206] Formulation with Compound A+Cyclodextrin 0.2% of dose applied.

[0207] This shows the surprising effect of the combined use of compound (A) with a cyclodextrin, that a 40-fold better permeation can be achieved, even by applying only a 2.5-fold dosis of the drug compound.

EXAMPLE 11

[0208] For testing of the long term preservation of the ophthalmic formulations with metal-containing preservatives, the pharmaceutical compositions VI of example 4 was modified by adding thiomersal in a concentration of 0.01% by weight in the aqueous formulation.

[0209] A long-time preservation against the organisms Candida albicans, Aspergillus niger, Pseudomonas aeruginosa and Staphylococcus aureus after 28 days was observed with a reduction of all for organisms of at least log 5.

[0210] By using the preservative sorbic acid (0.3% by weight) instead of thiomersal in the above mentioned ophthalmic formulation, already after 14 days an insufficient preservation against Candida albicans can be observed.

EXAMPLE 12

[0211] For testing the influence of the cyclodextrin content in ophthalmic formulations, the solubility of Compound (A) was tested. The equilibrium solubility (at 20 C.) of compound (A) in water without cyclodextrin was measured as 11.6 mg/ml.

[0212] The equilibrium solubility (at 20 C.) of compound (A) in water containing 65 mg/ml cyclodextrin (HPBCD) was measured as 20.2 mg/ml. The equilibrium solubility (at 20 C.) of compound (A) in water containing 165 mg/ml cyclodextrin was measured as 41.2 mg/ml.