WO1996014090A1

WO1996014090A1 - Compositions comprising carbazoles and cyclodextrins

Info

Publication number: WO1996014090A1
Application number: PCT/EP1995/004295
Authority: WO
Inventors: Jean Louis Mesens; Herman Maria Jozef Van Cauteren; Peter Putteman; Jozef Peeters
Original assignee: Janssen Pharmaceutica N.V.
Priority date: 1994-11-07
Filing date: 1995-10-31
Publication date: 1996-05-17
Also published as: IL115885A0; TR199501376A2; ZA959388B; AU3846395A

Abstract

This invention relates to pharmaceutical compositions carbazole derivatives of formula (I), wherein R1 and R4 each independently represent a hydrogen atom or a C1-6 alkyl group; each R2 may be the same or different and represents an electron-withdrawing group; each R3 may be the same or different and represents an electron-withdrawing group; R5 is a group of formula (a), (b) or (c); R6 is a halogen atom, a C1-6 alkyl group or a C1-6 alkyloxy group; m is zero or an integer 1 to 4; n is zero or an integer 1 to 3; and p is zero, 1 or 2; the pharmaceutically acceptable salts and solvates thereof, and cyclodextrins, to processes of preparing such compositions, and to their use for the manufacture of medicaments that reduce androgen and/or oestrogen levels in mammals, including humans.

Description

Compositions comprising carbazoles and cyclodextrins

This invention relates to pharmaceutical compositions comprising carbazole derivatives and cyclodextrins, to processes of preparing such compositions, and to their use for the manufacture of medicaments.

Carbazole derivatives of formula

wherein Ri and R4 each independently represent a hydrogen atom or a Ci-6alkyl group; each R2 may be the same or different and represents an electron-withdrawing group; each R3 may be the same or different and represents an electron-withdrawing group; R5 is a group of formula

R6 is a halogen atom, a Ci-6alkyl group or a Ci-6alkyloxy group; m is zero or an integer 1 to 4; n is zero or an integer 1 to 3; and p is zero, 1 or 2; the pharmaceutically acceptable salts and solvates thereof, are interesting inhibitors of the enzyme 17,20-lyase and as such are useful ingredients in medicines that reduce androgen and/or oestrogen levels in mammals, including humans. These compounds, their pre¬ paration and characteristics are disclosed in WO-94/27989 (PCT appl. No. EP 94.01613 filed on May 19, 1994 and claiming priority of GB 9310635.9, filed 21 May 1993).

The carbazoles of formula (I) are only sparingly soluble in neutral aqueous solutions. Most of them hardly form acid addition salt forms and thus they are poorly soluble in acidic aqueous solutions, too. Moreover, the carbazoles of formula (I) decompose in highly acidic media (about pH 1). Consequently, there is a need for efficaceous pharmaceutical compositions that allow one to administer meaningful dosages of the carbazole derivatives of formula (I) to the subjects to be treated. It has now been found that compositions of the carbazoles of formula (I), together with a cyclodextrin or a cyclodextrin derivative, and optionally one or more excipients or carriers as known in the art, lack the aforementioned bioavailability problem.

The present invention concerns pharmaceutical compositions comprising a compound of formula (I)

R6 is a halogen atom, a Ci-6al yl group or a Ci-6alkyloxy group; m is zero or an integer 1 to 4; n is zero or an integer 1 to 3; and p is zero, 1 or 2; or a pharmaceutically acceptable salt or solvate thereof as an active ingredient, a cyclodextrin or a cyclodextrin derivative as solubilizing agent, and optionally one or more pharmaceutical carriers or excipients.

The substituents R2 may each occupy any available position of the 5, 6, 7 or 8 positions.

The substituents R3 may each occupy any available position of the 1, 2, 3 or 4 positions, preferably the 1, 3 or 4 positions. The group CHR4R5 may occupy any of the 1, 2, 3 or 4 positions, for example, the 1, 2 or 3 positions. Preferably the group CHR4R5 will be in the 2 position.

Thus, in one aspect the invention provides compounds of formula (I^a)

wherein Ri, R2, R3, R4, R5, m and n are as hereinbefore defined.

The substituent R6 may be attached to any carbon atom in the pyridyl ring, but preferably is attached in the 3, 4 or 5 positions.

It will be appreciated by those skilled in the art that the numbering of the ring system for individual compounds within the scope of formula (I) will vary according to the nature, number and position of substituents. For convenience the numbering of ring atoms adopted herein is that shown in formula (I) above except where individual compound names are given.

It will be appreciated that the compounds of formula (I) may contain a chiral centre. It is to be understood that formula (I) is intended to encompass all enantiomers and diastereoisomers of the compounds of the invention as well as mixtures thereof, including racemates.

Electron- withdrawing groups are well known to those skilled in the art and any such group may be employed. Such groups include halogen atoms, such as fluorine, chlorine and bromine atoms, nitrile groups, nitro groups, trifluoromethyl groups, aldehydo groups, keto groups and carboxylic acid and ester groups and are preferably selected from fluorine atoms, chlorine atoms and nitrile groups. Particularly preferred as compounds of formula (I) are those wherein each of R2 and R3 represents a fluorine atom.

Suitably R2 represents a fluorine atom and m is an integer 1 to 4.

When m is 1, R2 will preferably be in the 5 or 7 position, especially the 7 position. Ci-6alkyl and Ci-6alkoxy groups may contain straight or branched chain alkyl groups, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, t-butyl, pentyl or hexyl groups, preferably Cl-4alkyl groups. Thus, for example, each of Ri and R4 may be a hydrogen atom or a methyl, ethyl, propyl or butyl group.

Rl and R4 are each preferably a hydrogen atom or a methyl group.

In one preferred group of compounds of formula (I) R5 is a pyridin-3-yl or pyridin-4-yl group.

Suitably R6 represents a fluorine atom, a methyl group or a methoxy group.

In a preferred group of compounds of formula (I), Rl and R4 each represent a hydrogen atom or a methyl group, R2 and R3 are fluorine atoms, R6 is a fluorine atom, a methyl group or a methoxy group, m is an integer 1 to 4, n is zero or an integer 1 to 3, and p is zero, 1 or 2.

In a particularly preferred group of compounds of formula (I), Ri and R4 each represent a hydrogen atom, R2 and R3 are fluorine atoms, R6 is a fluorine atom or a methyl or methoxy group and m, n and p each independently represent zero, 1 or 2.

Specific compounds according to the invention include:

2-Fluoro-7-[l, 2 ,4]triazol-l-ylmethyl-9H-carbazole 2-Fluoro-7-pyridin-3-ylmethyl-9H-carbazole

2-Fluoro-7-pyridin-4-ylmethyl-9H-carbazole

2-Huoro-7-(3-fluoropyridin-4-ylmethyl)-9H-carbazole

2-Ruoro-7-(3-methylpyridin-4-ylmethyl)-9H-carbazole

2-Fluoro-7-(3-methoxypyridin-4-ylmethyl)-9H-carbazole 1, 7-Difluoro-2-[l, 2, 4]triazol-l-ylmethyl-9H-carbazole

2, 4-Difluoro-7-[l, 2, 4]triazol-l-ylmethyl-9H-carbazole

1, 4 ,7 -Trifluoro-2-[l, 2, 4]triazol-l-ylmethyl-9H-carbazole and pharmaceutically acceptable salts and solvates thereof.

Suitable pharmaceutically acceptable salts of the compounds of formula (I) include acid addition salts derived from inorganic and organic acids, such as hydrochlorides, hydrobromides, sulphates, phosphates, citrates, tartrates, maleates, fumarates, succinates, p-toluenesulphonates and methanesulphonates. Other suitable salts will be readily apparent to one skilled in the art Hydrochloride, sulphate, phosphate and citrate salts are especially preferred. Salts which are not pharmaceutically acceptable may be useful in the preparation of compositions according to the present invention.

Particularly preferred for use in combination with cyclodextrin or a cyclodextrin derivative is the compound 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole mono- hydrochloride which has exceptionally high solubility and oral bio-availability.

The compounds according to the invention may be prepared by any process known in the art for the preparation of compounds of analogous structure. In the following description Rj, R2, R3, R4, R5, R6» m, n and p are as defined for general formula (I) unless otherwise specified.

In one general process (A), a compound of general formula (I) wherein Rj represents a hydrogen atom may be prepared from an intermediate of formula (II) by cyclisation.

The reaction is conveniently effected in the presence of a suitable solvent, such as a hydrocarbon solvent, for example dodecane, or a halogenated solvent, such as dichlorobenzene, preferably at elevated temperature, for example 100 to 300°C, preferably 150 to 220°C. General process (A) is particularly useful for the preparation of compounds of formula (I) wherein R5 is a triazole group.

Intermediates (II) may be prepared from the corresponding amines of formula (HT)

by treatment with sodium nitrite in the presence of a mineral acid, e.g. sulphuric acid, followed by sodium azide. The reaction is conveniently effected in aqueous solution. Compounds of formula (Iff) may be prepared from the corresponding nitro compounds of formula (TV)

by reduction using hydrogen or a hydrogen-donor, e.g. ammonium formate, in the presence of a catalyst, such as a noble metal catalyst, e.g. platinum, palladium, platinum oxide or rhodium, which may be supported, e.g. on charcoal. The reduction may be carried out in a solvent such as an alcohol e.g. methanol or ethanol (which may be aqueous), acetic acid, aqueous acetic acid, an ether e.g. dioxan, an ester e.g. ethyl acetate or an amide e.g. dimethylformamide, and conveniently at a temperature of from -10 to +50°C, preferably 20 to 30°C.

Compounds of formula (TV) may be prepared from compounds of formula (V)

by treatment with a compound of formula HR5 (1,2,4-triazole) or the sodium salt thereof. The reaction is conveniently effected in a suitable solvent, e.g dimethylformamide.

Intermediates of formula (V) may be prepared from compounds of formula (VI)

by free radical bromination, for example using N-bromosuccinimide in the presence of an initiator, such as a peroxide and/or ultra-violet light. The reaction is conveniently effected in a non-polar solvent, such as a halogenated solvent, e.g. chloroform or tetrachloromethane, at a temperature of 20 to 80°C.

Compounds of formula (VI) may be prepared from compounds of formula (VII)

wherein L represents a readily displaceable atom or group by reaction with a compound of formula (Vπi)

in the presence of a suitable palladium(O) catalyst such as tetrakis(triphenylphosphine) palladium (0) and a base, e g. sodium carbonate, in a suitable aqueous solvent such as an alcohol, e.g. ethanol, an aromatic hydrocarbon, e.g. benzene, or an ether, e.g. dimethoxyethane, or an aqueous mixture of solvents. Suitable atoms or groups represented by L include halogen atoms, e.g. bromine or iodine atoms, or a triflate group.

In another general process (B), a compound of formula (I) may be prepared from a compound of

by deoxygenation. The deoxygenation reaction is effected using a suitable reducing agent such as hydrogen in the presence of a catalyst, such as a noble metal catalyst, e.g. platinum, palladium, platinum oxide or rhodium, which may be supported, e.g. on charcoal. The reaction may conveniently be carried out in a solvent such as an alcohol, e.g. methanol or ethanol, which may be aqueous, in the presence of an acid, e.g. hydrochloric acid, preferably at elevated temperature, e.g. at the reflux temperature of the solvent or at elevated pressure. General process (B) is particularly useful for the preparation of compounds of formula (I) wherein R5 is a pyridyl group.

Intermediates of formula (LX) may be prepared from compounds of formula (X)

by reaction with compounds of formula Hal-R5 (XI) in the presence of a suitable base, such as an alkyllithium, e.g. n-butyllithium. The reaction is conveniently effected in the presence of a suitable solvent such as an ether, e.g. diethyl ether, dimethoxyethane or tetrahydrofuran, or a mixture of solvents, suitably at low temperature, e.g. -90 to -50°C, preferably about -70°C.

Compounds of formula (X) may be prepared from compounds of formula (XII)

Ri

by oxidation. Suitable oxidising agents will be readily apparent to one skilled in the art and include pyridinium chlorochromate, potassium dichromate in sulphuric acid and barium manganate. The reaction may conveniently be effected in the presence of a solvent, e.g. a halogenated solvent such as dichloromethane.

Compounds of formula (XII) may be prepared from compounds of formula (XIH)

by cyclisation. The reaction is conveniently effected in the presence of a suitable solvent, such as a hydrocarbon solvent, e.g. dodecane, or a halogenated solvent, e.g. dichloro- metiiane, preferably at elevated temperature, e.g. 100 to 300°C, preferably 150 to 220°C.

Compounds of formula (XLH) may be prepared from compounds of formula (XLV)

by treatment with sodium nitrite in the presence of a mineral acid, e.g. sulphuric acid, followed by sodium azide. The reaction is conveniently effected in aqueous solution.

Compounds of formula (XLV) may be prepared from compounds of formula (XV)

wherein G represents a hydroxy protecting group by reduction using hydrogen or a hydrogen-donor, e.g. ammonium formate, in the presence of a catalyst, such as a noble metal catalyst, e.g. platinum, palladium, platinum oxide or rhodium, which may be supported, e.g. on charcoal and subsequent removal of the protecting group G. The reduction may conveniently be carried out in a solvent such as an alcohol, e.g. methanol or ethanol, which may be aqueous, optionally in the presence of an acid, e.g. hydrochloric acid. References to hydroxy protecting groups are described under general process (D).

Compounds of formula (XV) may be prepared from compounds of formula (XVI)

wherein L represents a readily displaceable atom or group by reaction with a compound of formula (XVJT)

in the presence of a suitable palladium (0) catalyst such as tetrakis(triphenylphosphine) palladium (0) and a base, e.g. sodium carbonate, in a suitable aqueous solvent such as an alcohol, e.g. ethanol, an aromatic hydrocarbon, e.g. benzene, or an ether, e.g. dimethoxyethane, or an aqueous mixture of solvents preferably at elevated temperature. Suitable atoms or groups represented by L include a halogen atom, e.g. a bromine or iodine atom, and a triflate group.

Alternative synthetic routes to the intermediates of formula (X) will be readily apparent to those skilled in the art.

In another general process (C) a compound of formula (I) according to the invention may be converted into another compound of the invention using conventional procedures.

According to one embodiment of general process (C) a compound of formula (I) wherein Rl represents a hydrogen atom may be alkylated using conventional techniques. The reaction may be effected using a suitable alkylating agent such as an alkyl halide, alkyl tosylate or dialkylsulphate. The reaction may conveniently be carried out in an inert organic solvent such as an amide, e.g. dimethylformamide, or an ether, e.g. tetrahydrofuran, preferably in the presence of a base. Suitable bases include, for example, alkali metal hydrides, e.g. sodium hydride, alkali metal carbonates, e.g. sodium carbonate, or alkali metal alkoxides, e.g. sodium or potassium, methoxide, ethoxide or t-butoxide. The alkylation reaction is conveniently effected at a temperature offrom 25 to lOO°C.

According to another general process (D), a compound of formula (I) according to the invention or a salt thereof may be prepared by subjecting a protected derivative of formula (I) or a salt thereof to reaction to remove the protecting group or groups. Thus, at an earlier stage in the preparation of a compound of formula (I) or a salt thereof it may have been necessary and/or desirable to protect one or more sensitive groups in the molecule to prevent undesirable side reactions. Such protection may be effected in conventional manner, for example as described in 'Protective Groups in Organic Chemistry' Ed. J.F.W. McOmie (Plenum Press 1973) or 'Protective Groups in Organic Synthesis' by T. W. Greene (John Wiley and Sons 1981).

In compounds of formula (I) wherein Ri represents hydrogen the group NRi may be protected for example with a conventional amino protecting group. Such groups may include for example aralkyl groups, such as benzyl, diphenylmethyl or triphenylmethyl groups; and acyl groups such as tosyl, N-benzyloxycarbonyl or t-butoxycarbonyl.

Removal of any amino protecting groups present may be achieved by conventional procedures. Thus an aralkyl group such as benzyl, may be cleaved by hydrogenolysis in the presence of a catalyst (e.g. palladium on charcoal); an acyl group such as t-butoxycarbonyl may be removed by cleavage with, for example, hydrogen chloride in dioxan or sodium methoxide in methanol.

As will be appreciated, in some of the general processes (A) to (C) described above it may be necessary or desired to protect any sensitive groups in the molecule as just described. Thus, a reaction step involving deprotection of a protected derivative of general formula (I) or a salt thereof may be carried out subsequent to any of the above described processes (A) to (C).

Where it is desired to isolate a compound of the invention as a salt, for example as an acid addition salt, this may be achieved by treating the free base of general formula (I) with an appropriate acid, preferably with an equivalent amount Solvates of the compounds of the invention may be prepared by crystallisation from or evaporation of an appropriate solvent solution of the compounds of formula (I). Separation of enanuomers of formula (I) may be carried out in conventional manner, for example by resolution of racemic mixtures e.g. using chiral HPLC techniques or by stereospecific synthesis from isomerically pure starting material or any convenient intermediate, for example as described in Stereochemistry of Carbon Compounds by E.L. Eliel (McGraw Hill, 1962) and Tables of Resolving Agents by S.H. Wilen.

The compounds according to the invention are potent and selective inhibitors of the enzyme steroidal 17,20-lyase, which is a key enzyme involved in the conversion of C21 -steroids (e.g. pregnenolone) into androgens (e.g. testosterone) and oestrogens (e.g. oestradiol). The 17,20-lyase-inhibiting activity of the compounds of formula (I) can be demonstrated in vitro by their ability to inhibit the conversion of 17-α-hydroxypregnenolone into dehydroepiandrosterone by human testicular 17,20-lyase, and of 17-α-hydroxypro- gesterone into androstenedione by rat testicular 17,20-lyase. These assays were conducted according to a method based on that of Ayub and Level, J. Steroid Biochem, 1987, 28, 521.

In in vivo tests the compounds of the invention have been tested for their ability to suppress the elevation of testosterone levels produced in male rats when stimulated with human chorionic gonadotrophin (hCG).

Inhibitors of 17,20-lyase reduce circulating and local levels of androgens and oestrogens. The compositions of the invention can thus be used in the treatment of androgen- and/or oestrogen-dependant diseases such as malignant and benign diseases of the breast, endometrium, ovary, prostate and pancreas. These diseases include cancer of the prostate, breast and endometrium, prostatic hypertrophy and hyperplasia, fibrocystic breast disease, endometriosis and polycystic ovarian disease. The compounds of formula (I) are also useful in the treatment of Cushing's syndrome, gynecomastia, premature labour, precocious puberty, female hirsutism, premenstrual syndrome, male pattern baldness and acne. The compounds of formula (I) will be particularly useful in the treatment of prostate cancer.

Appropriate cyclodextrins for use in the present compositions are α-, β-, γ-cyclodextrins or ethers and mixed ethers thereof wherein one or more of the hydroxy groups of the anhydroglucose units of the cyclodextrin are substituted with Cι_5alkyl, particularly methyl, ethyl or isopropyl, e.g. randomly methylated β-CD; hydroxyCι_6alkyl, particularly hydroxyethyl, hydroxypropyl or hydroxybutyl; carboxyCι_6alkyl, particularly carboxymethyl or carboxyethyl; Ci^alkylcarbonyl, particularly acetyl; Cι.6alkyloxycarbonylCι.6alkyl or carboxy-Ci-6alkyloxyCι_6alkyl, particularly carboxymethoxypropyl or carboxyethoxypropyl; Cι-6alkylcarbonyloxyCι-6alkyl, particularly 2-acetyloxypropyl. Especially noteworthy as complexants and/or solubilizers are β-CD, randomly methylated β-CD, 2,6-dimethyl-β-CD, 2-hydroxyethyl- β-CD, 2-hydroxyethyl-γ-CD, 2-hydroxypropyl-γ-CD and (2-carboxymethoxy)propyl-β-

CD, and in particular 2-hydroxypropyl-β-CD (2-HP-β-CD). The term mixed ether denotes cyclodextrin derivatives wherein at least two cyclodextrin hydroxy groups are etherified with different groups such as, for example, hydroxy- propyl and hydroxyethyl.

The average molar substitution (M.S.) is used as a measure of the average number of moles of alkoxy units per mole of anhydroglucose. The M.S.value can be determined by various analytical techniques such as nuclear magnetic resonance (NMR), mass spectrometry (MS) and infrared spectroscopy (LR). Depending on the technique used, slighUy different values may be obtained for one given cyclodextrin derivative. In the cyclodextrin hydroxyalkyl derivatives for use in the compositions according to the present invention the M.S. as determined by mass spectrometry is in the range of 0.125 to 10, in particular of 0.3 to 3, or from 0.3 to 1.5. Preferably the M.S. ranges from about 0.3 to about 0.8, in particular from about 0.35 to about 0.5 and most particularly is about 0.4. M.S. values determined by NMR or LR preferably range from 0.3 to 1, in particular from 0.55 to 0.75.

The average substitution degree (D.S.) refers to the average number of substituted hydroxyls per anhydroglucose unit The D.S. value can be determined by various analytical techniques such as nuclear magnetic resonance (NMR), mass spectrometry (MS) and infrared spectroscopy (LR). Depending on the technique used, slightly different values may be obtained for one given cyclodextrin derivative. In the cyclodextrin derivatives for use in the compositions according to the present invention the D.S. as determined by MS is in the range of 0.125 to 3, in particular of 0.2 to 2 or from 0.2 to 1.5. Preferably the D.S. ranges from about 0.2 to about 0.7, in particular from about 0.35 to about 0.5 and most particularly is about 0.4. D.S. values determined by NMR or LR preferably range from 0.3 to 1, in particular from 0.55 to 0.75.

More particular β- and γ-cyclodextrin hydroxyalkyl derivatives for use in the compositions according to the present invention are partially substituted cyclodextrin derivatives wherein the average degree of alkylation at hydroxyl groups of different positions of the anhydroglucose units is about 0% to 20% for the 3 position, 2% to 70% for the 2 position and about 5% to 90% for the 6 position. Preferably the amount of unsubstituted β- or γ-cyclodextrin is less than 5% of the total cyclodextrin content and in particular is less than 1.5%. Another particularly interesting cyclodextrin derivative is randomly methylated β-cyclodextrin. Most preferred cyclodextrin derivatives for use in the present invention are those partially substituted β-cyclodextrin ethers or mixed ethers having hydroxypropyl, hydroxyethyl and in particular 2-hydroxypropyl and/or 2-(l -hydroxypropyl) substituents.

The most preferred cyclodextrin derivative for use in the compositions of the present invention is 2-hydroxypropyl-β-cyclodextrin having a M.S. (as determined by mass spectrometry) in the range of from 0.35 to 0.50 and containing less than 1.5% unsubstituted β-cyclodextrin. M.S. values determined by NMR or LR preferably range from 0.55 to 0.75.

Substituted cyclodextrins can be prepared according to procedures described in US-3,459,731, EP-A-0,149,197, EP-A-0, 197,571, US-4,535,152, WO-90/12035 and GB-2, 189,245. Other references describing cyclodextrins for use in the compositions according to the present invention, and which provide a guide for the preparation, purifϊ- cation and analysis of cyclodextrins include the following : "Cyclodextrin Technology" by Jόzsef Szejtli, Kluwer Academic Publishers (1988) in the chapter Cyclodextrins in Pharmaceuticals; "Cyclodextrin Chemistry" by M.L. Bender et al., Springer- Verlag, Berlin (1978); "Advances in Carbohydrate Chemistry", Vol. 12 Ed. by M.L. Wolfrom, Academic Press, New York (157) in the chapter The Schardinger Dextrins by Dexter French at p. 189-260; "Cyclodextrins and their Inclusions Complexes" by J. Szejtli, Akademiai Kiado, Budapest, Hungary (1982); I. Tabushi in Ace. Chem. Research, 1982, 11, p. 66-72; W. Sanger, Angewandte Chemie, 91, p. 343-361 (1981); A. P. Croft and R. A. Bartsch in Tetrahedron, 3_9_, p. 1417-1474 (1983); Irie et al. Pharmaceutical Research, 5_, P- 713-716, (1988); Pitha et al. Int. J. Pharm. 29_, 73, (1986); DE 3,118,218; DE-3,317,064; EP-A-94,157; US-4,659,696; and US-4,383,992.

The pharmaceutical compositions according to the present invention may consist of only the carbazole derivative of formula (I) and the cyclodextrin or cyclodextrin derivative. Such form is particularly useful for reconstitution with water, saline or an aqueous solution of the cyclodextrin; but also for preparing the pharmaceutical compositions described in the following paragraphs. This solid form can conveniendy be prepared by lyophilization of an aqueous solution of the active ingredient and the cyclodextrin. Alternatively, said solid form can also be prepared by extrusion of the components, in particular by melt extrusion. Interestingly, it was found that melt extrusion of a 1 to 1 molar ratio of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole with 2-hydroxypropyl-β- cyclodextrin yielded a metastable solid solution whereas at higher proportions of cyclodextrin derivative, e.g. at a 1 to 3 molar ratio of 2-fluoro-7-(3-pyridinylmethyl)- 9H-carbazole with 2-hydroxypropyl-β-cyclodextrin, a stable solid solution of the components was obtained. Grinding of the thus obtained product yielded a solid form having excellent dissolution characteristics, in particular a rapid and total dissolution. The extruded material further proved to be an excellent starting composition for preparing other solid forms such as tablets and capsules (as described hereinafter).

Preferably, however, the pharmaceutical compositions according to the present invention comprise one or more excipients or carriers as known in the art. By appropriately selecting one or more of these excipients or carriers, the pharmaceutical compositions are adapted for oral, rectal, vaginal, topical, parenteral (including intramuscular, subcutaneous and intravenous) or implant administration, or in a form suitable for administration by inhalation or insufflation. The formulations may, where appropriate, be conveniently presented in discrete dosage units.

For oral administration, the pharmaceutical compositions may take the form of solid dose forms, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g. pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g. lactose, microcrystalline cellulose or calcium phosphate); lubricants e.g. magnesium stearate, talc or silica); disintegrants (e.g. potato starch or sodium starch glycollate); or wetting agents (e.g. sodium lauryl sulphate). The tablets may be coated by methods well known in the art.

Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means, optionally with pharmaceutically acceptable additives such as suspending agents (e.g. sorbitol syrup, methylcellulose, hydroxypropyl methylcellulose or hydrogenated edible fats); emulsifying agents (e.g. lecithin or acacia); non-aqueous vehicles (e.g. almond oil, oily esters or ethyl alcohol); and preservatives (e.g. methyl or propyl p-hydroxybenzoates or sorbic acid).

As a bulk liquid carrier there may be used an acidic aqueous medium. Preferably the acidity of said carrier derives from a pharmaceutically acceptable acid such as described above in the definition of 'salts', in particular hydrochloric acid, phosphoric acid, citric acid or mixture thereof. The bioavailability of the carbazole derivative and the stability of the liquid formulations are affected contrariwise by increasing acidity. An optimum effect can be obtained at pH 2.0 ± 0.1 : that is, at this pH value, a sufficiently bioavailable formulation is obtainable, the stability of which is entirely satisfactory.

Besides the acid taste due to the low pH, a bitter taste originating from the active ingredient, and possibly from the non-aqueous vehicle, may be also present Taste masking can be obtained by the use of adjuvants, namely pharmaceutically acceptable sweeteners and/or flavours. Sweeteners are usually the more important additives in the low-dosage formulations, whereas the flavours are usually more important in the high- dosage formulations.

Pharmaceutically acceptable sweeteners comprise preferably at least one intense sweetener such as saccharin, sodium or calcium saccharin, aspartame, acesulfame potassium, sodium cyclamate, alitame, a dihydrochalcone sweetener, monellin, stevioside or sucralose (4, ,6'-trichloro-4, ,6'-trideoxyj α/flctosucrose), preferably saccharin, sodium or calcium saccharin, and optionally a bulk sweetener such as sorbitol, mannitol, fructose, sucrose, maltose, isomalt, glucose, hydrogenated glucose syrup, xylitol, caramel or honey.

Intense sweeteners are conveniently employed in low concentrations. For example, in the case of sodium saccharin, the concentration may range from 0.04% to 0.1 % (w/v) based on the total volume of the final formulation, and preferably is about 0.06% in the low-dosage formulations and about 0.08% in the high-dosage ones. The bulk sweetener can effectively be used in larger quantities ranging from about 10% to about 35%, preferably from about 10% to 15% (w/v). In the high-dosage formulations the cyclodextrin derivative behaves as a bulk sweetener and none of the aforementioned bulk sweeteners needs to be added.

The pharmaceutically acceptable flavours which can mask the bitter tasting ingredients in the low-dosage formulations are preferably fruit flavours such as cherry, raspberry, black currant or strawberry flavour. A combination of two flavours may yield very good results. In the high-dosage formulations stronger flavours may be required such as Caramel Chocolate flavour, Mint Cool flavour, Fantasy flavour and the like pharmaceutically acceptable strong flavours. Each flavour may be present in the final composition in a concentration ranging from 0.05% to 1% (w/v). Combinations of said strong flavours are advantageously used. Preferably a flavour is used that does not undergo any change or loss of taste and colour under the acidic conditions of the formulation. A low-dosage oral formulation according to the present invention typically comprises from about 2% to about 20% (w/v), preferably about 5% (w/v) of the cyclodextrin and about 0.1% (w/v) active ingredient. A high-dosage formulation typically comprises from about 10% to about 60% (w/v), preferably from about 20% (w/v) to about 30% (w/v) of the cyclodextrin derivative and about 0.5% (w/v) active ingredient.

A very high-dose oral formulation according to the present invention comprises from about 5% to about 20%, preferably about 10% (w/v) of the cyclodextrin and from 0.5% to about 2.5%, in particular about 1% (w/v) of 2-fluoro-7-(3-pyridinylmethyl)-9H- carbazole monohydrochloride. Very high-dose formulations are particularly suitable for treating patients suffering from those conditions wherein it is essential to maintain constant, high plasm levels of the carbazole drug and the amount of cyclodextrin carrier administered approaches the maximum oral tolerability.

Suitable oral formulations can be prepared following the steps :

(a) acidifying an amount of water to about pH 1.7 with an acid, in particular IN HC1;

(b) dissolving therein the cyclodextrin derivatives;

(c) next dissolving the active ingredient therein; (d) adjusting the pH to about pH 2.0, and

(e) diluting the thus obtained solution to the final volume.

In order to increase the degree and rate of dissolution of the poorly soluble carbazole derivative during the manufacturing process, an alcoholic co-solvent may be employed in the formulations according to the present invention. For this purpose, preference is given to those alcoholic co-solvents that have good dissolving power, in particular ethanol, propylene glycol and especially polyethylene glycol 400. Without the alcoholic co-solvent, the dissolution of the active ingredient in an aqueous acidic cyclodextrin medium may be slow. Addition of the alcoholic co-solvent, in the range of about 1 % (v/v) to about 20% (v/v), preferably about 10% (v/v), usually increases the dissolution rate of the active agent in an aqueous acidic cyclodextrin medium considerably and thus may shorten and simplify the production process.

For topical administration in the mouth, the pharmaceutical compositions may take the form of buccal or sub-lingual tablets, drops or lozenges formulated in conventional manner. For topical administration to the epidermis the compounds of the invention may be formulated as creams, gels, ointments or lotions or as transdermal patches. Such compositions may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening, gelling, emulsifying, stabilising, dispersing, suspending, and/or colouring agents.

The compounds of the invention may also be formulated as depot preparations. Such long acting formulations may be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the compounds may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example as a sparingly soluble salt.

The compounds of the invention may be formulated for parenteral administration by injection, conveniently intravenous, intramuscular or subcutaneous injection, for example by bolus injection or continuous intravenous infusion. Formulations for injection may be presented in unit dosage form e.g. in ampoules or in multidose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as isotonizing, suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g. sterile pyrogen-free water before use.

The compounds of the invention may also be formulated in rectal compositions such as suppositories or retention enemas, e.g. containing conventional suppository bases such as cocoa butter or other glycerides.

For intranasal administration the compounds of the invention may be used, for example, as a liquid spray, as a powder or in the form of drops.

For administration by inhalation the compounds according to the invention are conveniently delivered in the form of an aerosol spray presentation from pressurised packs or a nebuliser, with the use of a suitable propellant, e.g. dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, 1,1,1,2-tetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurised aerosol the dosage unit may be determined by providing a valve to deliver a metered amount Capsules and cartridges of e.g. gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of a compound of the invention and a suitable powder base such as lactose or starch.

Any of the pharmaceutical compositions described above may be presented in a conventional manner associated with controlled release forms.

Preferably, the pharmaceutical compositions according to the invention are suitable for oral, rectal or topical administration.

Processes of preparing the compositions as claimed are well known in the art of pharmacy and are characterized in that the active ingredient, the cyclodextrin or cyclodextrin derivative, and optionally the excipient, are intimately mixed with one another. All methods include the step of bringing into association the active compound with liquid carriers or finely divided solid carriers or both and then, if necessary, shaping the product into the desired formulation.

The compositions may advantageously be presented in discrete dose units, especially in unit dosage forms. A convenient unit dose formulation contains the active ingredient in an amount of from 10 to 200 mg, preferably an amount of from 50 to 100 mg.

It will be appreciated that the amount of a compound of formula (I) required for use in treatment will vary not only with the particular compound selected, but also with the route of administration, the nature of the condition being treated and the age, weight and condition of the patient and will ultimately be at the discretion of the attendant physician or veterinarian. In general, however, a suitable dose will be in the range of from about 1 to about 500 mg per day, preferably in the range of 50 to 400 mg per day, most preferably in the range of 100 to 300 mg per day.

For treating patients suffering from prostate cancer the suitable dose will be in the range of 400 to 1000 mg per day, most preferably in the range of 700 to 800 mg per day. In order to minimize the patients' discomfort, the very high-dose oral formulations described hereinbefore are the preferred presentations for administrati ..

A suitable daily dose for use in prophylaxis will generally be in the range of 0.1 mg to 50 mg. The desired dose may conveniendy be presented in a single dose or as divided doses administered at appropriate intervals, for example as two, three, four or more sub-doses per day. The compound is conveniently administered in unit dosage form.

The compound 2-fluoro-7-(3-pyridinylmethyl)-9Ii-carbazole monohydrochloride is preferably administered to human patients in two or more subdoses per day so as to obtain constantly effective, non-toxic plasm levels.

The molar ratio of active ingredient : cyclodextrin can range from 1 : 1 to 1 : 100, preferably from 1:5 to 1:25 and in particular from 1:8 to 1:13.

In the high-load compositions of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole monohydrochloride with cyclodextrin said ratio ranges from 2: 1 to 1 : 10 and in particular from 1:1 to 1:3.

The compositions of the present invention may also be used in combination with other therapeutic agents, for example, other androgen and/or oestrogen lowering agents, or anticancer agents. In particular the compositions of the invention may be employed together with known anticancer agents.

The invention thus provides, in a further aspect, a combination comprising a composition as defined herein, together with another therapeutically active agent in particular an anticancer agent.

The combination referred to above may conveniently be presented in the form of a single pharmaceutical formulation.

When compositions of compounds of formula (I) are used in combination with a second therapeutic agent, the compositions may be administered either sequentially or simultaneously by any of the routes described above.

Suitable therapeutic agents for use in the combinations defined above include, for example cyproterone acetate, flutamide and nilutamide (Anandron®).

When compounds of formula (I) are used in combination with a second therapeutic agent effective to reduce levels of androgens and/or oestrogens in a mammal including a human, the dose of each compound may vary from that when the compound is used alone. Thus when compounds of formula (I) are used together with a second therapeutic agent the dose of each compound may be the same or different to that employed when the compound is used alone. Appropriate doses will be readily appreciated by those skilled in the art.

Experimental part

Example 1 : Solubility test results in function of pH and amount of solubilizing agent. Several stock solutions of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in distilled water were prepared and brought to the required pH using a phosphate / citrate buffer. The concentrations of cyclodextrin ranged from 2.5% to 10% (w/v), the pH values from about 2 to about 4.

An excess of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole (compound 1) was added to each of the test solutions and mechanically agitated for six days at room temperature. The actual pH value was measured. The test solutions were then filtered and the amount of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole in solution was determined by U.V. spectroscopy.

The solubility data (mg/ml) are summarized in the table below. K_s values were calculated from the solubility data.

% HP-β-CD pH - - 2 H . - 3 pH - - 4 pH solubility pH solubility pH solubihty measured measured measured

0 2.40 0.20 2.89 0.084 3.94 0.0085

2.5 2.46 0.85 2.94 0.40 3.98 0.10

5 2.49 1.36 2.99 0.73 4.00 0.18

7.5 2.53 1.76 3.02 0.93 4.06 0.24

10 2.56 2.29 3.07 1.28 4.09 0.32

Ks 1071/mol 1601/mol 235 1/mol

Example 2 : Solubility test results in function of co-solvent

Following the methodology of example 1 , the solubility of 2-fluoro-7-(3-pyridinyl- methyl)-9H.-carbazole was measured in different solvents which are suitable as co-solvents for pharmaceutical preparations. The following results were obtained. solvent solubility (mgΛnl) propylene glycol 10.92 polyethylene glycol 400 (PEG 400) > 50 ethanol 20.88

Example 3

Four oral formulations for physicochemical stability testing and for dose finding studies were prepared with 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole. Distilled water was acidified with IN HC1 to about pH 1.7. A first oral solution was prepared therefrom by dissolving 200 g of 2-hydroxypropyl-β-cyclodextrin in about 700 to 800 ml of the acidified water. Next 5 g of the active ingredient 2-fluoro-7-(3-pyridinylmethyl)-9H- carbazole were dissolved in the aqueous solution. Upon complete dissolution, the pH of the solution was adjusted to pH 2.0 with a sodium hydroxide solution and diluted to an end- volume of 11. The final pH value was about pH 2.15. The solution did not deteriorate in any respect after 1 week storage at 60°C or 1 week storage in a light cabinet (17000 lux). A low-dosage formulation with 1 g of the active ingredient and 50 g HP-β-CD was prepared in the same manner and had similar physicochemical characterics. Another high-dosage formulation with 5 g of the active ingredient and 300 g HP-β-CD was prepared following the above method and also had positive stability characteristics. A fourth formulation with 400 g HP-β-CD and 20 g of the active ingredient was prepared following similarly. The resulting solution had appropriate physicochemical characteristics.

Example 4 : Preparation of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole monohydrochloride (Compound 2).

A mixture of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole (2 g) in 10 ml of acetone was stirred at reflux temperature. A solution of 2.44 ml of 2-propanol saturated with hydrochloric acid was added to the heterogenous mixture, which instantly turned homogenous. The reaction mixture was allowed to cool to room temperature, and was then stirred for one hour at 0°C. The precipitated salt was filtered off, washed with acetone (2 x 5 ml) and dried in vacuo, yielding 2.2 g (97.3%) of 2-fluoro-7-(3- pyridinylmethyl)-9H-carbazole monohydrochloride (mp. 180°C). Example 5 : Solubility test results in function of amount of solubilizing agent.

Several stock solutions of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in distilled water were prepared. The concentrations of cyclodextrin ranged from 2.5% to 10% (w/v). An excess of 2-fluoro-7-(3-pyrid ylmethyl)-9H.-carbazole monohydrochloride (compound 2) was added to each of the test solutions and mechanically agitated for six days at room temperature. The actual pH value was measured. The test solutions were then filtered and the amount of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole in solution was determined by U.V. spectroscopy. The solubility data (mg/ml) are summarized in the table below.

% HP-β-CD actual pH solubility (mg base / ml)

0 3.25 0.027

2.5 2.54 6.88

5 2.53 11.26

7.5 1.85 21.22

10 2.21 24.98

Example 6 : Solubility test results in function of co- solvent.

Following the methodology of example 1, the solubihty of 2-fluoro-7-(3-pyridinyl- methyl)-9H-carbazole monohydrochloride (compound 2) was measured in different solvents which are suitable as co-solvents for pharmaceutical preparations. The following results were obtained.

solvent solubihty propylene glycol > 50 (mg/g) glycerine 45.8 (mg g) ethanol > 50 (mg/g) polyethylene glycol 400 (PEG 400) > 50 (mg g) acetone 1 (mg ml)

Example 7 : Oral formulations of Compound 2.

Several oral formulations with a high ratio of active ingredient to carrier were prepared using 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole monohydrochloride and 2-hydroxy- propyl-β-cyclodextrin. 10 g of the cyclodextrin was dissolved into about 850 ml of distilled water. To four such solutions there were added respectively :

(a) 22.64 g (20 g),

(b) 19.81 g (17.5 g),

(c) 16.98 g (15 g), and

(d) 11.32 g (10 g) of 2-fluoro-7-(3-pyridinylmethyl)-9H-carbazole monohydrochloride (the weights between brackets are those of the base form of the active ingredient). After diluting the solutions to an end-volume of one litre, they were stirred until homogenous. Three solutions with 0.05 % of the suspending agent HPMC 29105 cps were prepared in a similar manner. The solutions are currently in stability tests.

Example 8 : Bioavailability of Compound 1 and Compound 2

4 Male beagle dogs were treated orally with 5 mg 2-fluoro-7-(3-pyridinylmethyl)-9H- carbazole per kg body weight. The active ingredient was administered either as the base compound 1 or as the acid addition salt compound 2, each formulated into a gelatin capsule. Plasm levels of the active ingredient were determined using HPLC. From these, the following data were calculated :

From these data it appears that the AUC and Cmax of compound 2 are approximately three times larger those of compound 1. Actually, in three of the four dogs, the difference between compound 2 and compound 1 was even higher, but in one dog the compound 1 resulted in higher plasm levels dian compound 2, and this reverse response explains the large standard deviations in the above data.

Claims

1. A pharmaceutical composition comprising a compound of formula

wherein Ri and R4 each independendy represent a hydrogen atom or a Ci-6alkyl group; each R2 may be the same or different and represents an electron-withdrawing group; each R3 may be the same or different and represents an electron-withdrawing group; R5 is a group of formula

R6 is a halogen atom, a Ci-6alkyl group or a Cl-6alkyloxy group; m is zero or an integer 1 to 4; n is zero or an integer 1 to 3; p is zero, 1 or 2; or a pharmaceutically acceptable salt or solvate thereof as an active ingredient, a cyclodextrin or a cyclodextrin derivative as solubilizing agent, and optionally one or more pharmaceutical carriers or excipients.

2. A composition according to claim 1 comprising as the active ingredient 2-fluoro-7-(3- pyridinylmethyl)-9H-carbazole or a pharmaceutically acceptable acid addition salt form thereof.

3. A composition according to claim 2 comprising 2-fluoro-7-(3-p^,'ridinylmethyl)-9H- carbazole monohydrochloride.

4. A composition according to any one of claims 1 to 3 wherein the cyclodextrin derivative is 2-hydroxypropyl-beta-cyclodextrin.

5. A composition according to any one of claims 1 to 4 adapted for oral, rectal, vaginal, parenteral, topical or implant administration.

6. A composition according to claim 1 formulated as a solid dose form for oral administration.

7. A composition according-to claim 1 formulated as liquid preparation for oral administration.

8. A composition according to claim 1 formulated as liquid preparation for parenteral administration.

9. A composition according to claim 1 formulated as a solution suitable for intravenous administration.

10. A composition according to claim 1 which is formulated in unit dosage form comprising 10 to 200 mg active ingredient.

11. A process of preparing a composition as claimed in any one of claims 1 to 10 characterized in that the active ingredient, the cyclodextrin or cyclodextrin derivative, and optionally the excipient are intimately mixed with one another.