DEAZAPURINE NUCLEOSIDE, FORMULATIONS THEREOF, AND USE THEREOF IN THERAPY

Abstract: The use of 3-deazaadenosine, 4-amino-1-β-D-­ ribofuranosyl-1H-imidazo-[4,5-c] pyridine, for the treatment of inflammation in mammals, including man, is disclosed. Pharmaceutical formulations suitable for administration of the compound, in particular topical formulations for local application, are also disclosed.

Description: DEAZAPURINE NUCLEOSIDE, FORMULATIONS THEREOF-, AND USE THEREOF IN THERAPY The present invention is concerned with compounds useful in medicine. More specifically it is concerned with the treatment of inflammation by the administration of an adenosine analogue. United States Patent No. 4 148 888 discloses 3-deazaadenosine, 4-amino-l-B-D-ribofuranosyl-l H-imidazolil,5--pyri dine, as an antiviral and antifocal agent. United Kingdom Patent Application No. 40447/78 discloses 3-deazaadeno sine as an immunosuppresant. 3-Deazaadenosine has now been suprisingly found to possess anti-inflam matory activity and is thus useful in the treatment of inflammation and thus disease conditions associated with inflammation. The invention accordingly provides a method for the treatment of inflam mation in mammals including humans suffering from an inflammatory condition, which comprises the administration of an anti-inflammatory, non-toxic amount of 3-deazaadenosine or a pharmaceutically acceptable salt thereof. By the term 'inflammation' is meant the reactive state of hyperaemia and exudation from its blood vessels, with consequent redness, heat, swelling and pain, which a tissue enters in response to physical or chemical injMrf if bacterial invasions. Clinical conditions with which inflammation is associated, and hence for which an anti-inflammatory agent is indicated, include for example arthritis, including rheumatoid arthritis and osteoarthritis, post operative inflammation, dental inflammation, acute and chronic ocular inflammatory diseases, conjunctivitis. 3-Deazaadenosine has been found to be a potent, long-acting antiinflammatory agent and is effective orally, systemically and locally. 3-Deazaadenosine is useful in the treatment of both acute and chronic inflammation. 3-Deazaadenosine has been found to inhibit both developing and established adjuvant arthritis, an animal model in the rat of human rheumatoid arthritis, and is thus particularly useful in the treatment of acute and chronic rheumatoid arthritis. The mechanism of the anti-inflammatory action of 3-deazaadenosine is at present unknown. It is not antipyretic and has no analgesic activity per se, and in this respect is like steroidal anti-inflammatory drugs such as prednisolone and hydrocortisone and like these known drugs will give relief from pain in may clinical syndromes by reducing inflammation. 3-Deazaadenosine does not inhibit protaglandin metabolism in vitro through either the lipoxygenase or cyclooxygenase pathway and is thus free of the side effects, particularly gastric damage and inhibition of platelet aggregation, associated with prostaglandin inhibitors such as aspirin. 3-Deazaadenosine is also free of the side effects of the anti-inflammatory steroids and unlike compounds such as acetaminophen (paracetamol) does not cause liver damage in the animal models used. Although its mechanism of action is different to that of aspirin, 3deazaadenosine is similar to aspirin in that it has a long duration of action (about 15 hours) associated with a short half life. Thus 3-deazaadenosine will require relatively infrequent administration for example twice daily and the problem of morning stiffness and associated pain and crippling effects in patients with arthritic conditions may be alleviated, in contrast to the shorter acting nonsteroidal and steroidal anti-inflammatory agents which do not possess this property. In addition 3-deazaadenosine, by virtue of its different mode of action to aspirin, salicylates and steroids, may be combined with such drugs to provide a 'sparing effect' reducing the required dose of these drugs and hence the side effects associated therewith. 3-Deazaadenosine is also advantageous in possessing a high therapeutic index and thus is unlikely to present problems associated with accidental overdose. Its high water solubility is a yet further advantage. The amount of 3-deazaadenosine required to reduce inflammation is relatively low and lies in the range of about 0.1 to about 30 mg/kg per day, particularly about 0.2 to about 5 mg/kg per day, preferably about 0.3 to about 1 mg/kg per day. In contrast immunesuppression requires more than 30 mg/kg and antiviral activity requires 100-200 mg/kg per day. Thus effects associated with other activities of 3-deazaadenosine, in particular suppression of the immune response, are exprected to be absent or minimal at the dose range required for anti-inflammatory activity. As 3-deazaadenosine is effective for both chronic and acute, i.e. both long and short term, inflammation, the compound may be administered for as long as the inflammation remains, which may be for several hours to a number of years. When 3-deazaadenosine is administered in the form of a pharmaceutically acceptable salt then the salt will be non-toxic salt, suitably an acid addition salt. Suitable salts include those derived from hydrochloric acid, hydroiodic acid, sulphuric acid, phosphoric acid, acetic acid, p-toluene sulphonic acid, methane sulphonic acid, maleic acid, lactic acid, citric acid, tartaric acid, succinic acid, oxalic acid, p-chlorobenzenesulphonic acid, isethionic acid, glucuronic acid, pantothenic acid, and lactobionic acid. While it is possible for 3-deazaadenosine or a pharmaceutically acceptable salt thereof (hereinafter referred to as "the active compounds") to be administered as the raw chemical it is preferably presented in the form of a pharmaceutical formulation. A pharmaceutical formulation will comprise an active compound together with a pharmaceutically acceptable carrier therefor. The carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. The pharmaceutical formulations may be prepared by any of the methods well known in the art of pharmacy all of which involve bringing the active compound into association with the carrier therefor. 3-Deazaadenosine is effective as an anti-inflammatory agent not only orally and systemically but also locally and is thus particularly suitable for topical administration. The term "topical" as applied herein relates to the use of the active ingredient incorporated in a suitable pharmaceutical carrier, and applied at the site of the disease for exertion of local actici, Included within the scope of topical formulations are ophthalmic formulations. Pharmaceutical formulation suitable for topical administration may be presented in anhydrous forms such as lotions, jellies, sprays, aerosols, bath oils or preferably ointments. The term ointment includes formulations (including creams) having oleaginous, absorption, water-soluble and emulsion type bases, for example petrolatum, lanolin, polyethylene glycols and mixtures thereof. Ointments are semi-solid materials with the active compound dispersed therein. These and other topical formulations enable the active ingredient to be applied and retained locally at the site of the disease. Topical formulation may contain a concentration of the active compound of from about 0.01 to about 10% w/w preferably about 0.1 to about 1% w/w most preferably about 0.2 to about 0.5% w/w. Topical formulations may be applied locally one or more times daily, as required. Other pharmaceutical formulations include those suitable for oral, rectal, and parenteral administration although of these oral is preferred. The formulations may, where appropriate, be conveniently presented in discrete dosage units and may be prepared in any of the methods well known in the art of pharmacy. A convenient unit dose formulation contains the active compound in an amount of from 5 mg to 250 mg, preferably 10 to 100 mg, most preferably about 50 mg to be taken once several times daily. All methods for the preparation of such formulations 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 products into the desired formulation. Pharmaceutical formulations suitable for oral administration wherein the carrier is a solid are most preferably presented as unit dose formulations such as boluses, capsules, cachets or tablets each containing a predetermined amount of the active compound. A tablet may be made by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active compound in a free-flowing form such as a powder or granules optionally mixed with a binder, lubricant, inert diluent, lubricating, surface active or dispersing agent. Tablets may be optionally coated and, if uncoated, may be optionally scored. Capsules may be prepared by filing the active compound either alone or in admixture with one or more accessory ingredients, into the capsule cases and then sealing them in the usual manner. Cachets are analogous to capsules wherein the active ingredients together with any accessory ingredient(s) are sealed in a rice paper envelope. Pharmaceutical formulations suitable for oral administration wherein the carrier is a liquid may be presented as a solution or a suspension in an aqueous liquid, or as an oil-in-water or water-in-oil liquid emulsion. Pharmaceutical formulations suitable for rectal administration wherein the carrier is a solid are most preferably presented as unit dose suppositories. Suitable carriers include cocoa butter and other material commonly used in the art, and the suppositories may be conveniently formed by admixture of the active compound with the softened or melted carrier(s) followed by chilling and shaping in moulds. Pharmaceutical formulations suitable for parenteral administration include sterile solutions or suspensions of the active compound in aqueous or oleaginous vehicles. Such preparations are conveniently presented in unit dose or multidose containers which are sealed after introduction of the formulation until required for use. It should be understood that in addition to the aforementioned carrier ingredients the pharmaceutical formulations described above may include, as appropriate, one or more additional carrier ingredients such as diluents, buffers, flavouring agents, binders, surface active agents, thickeners, lubricants, preservatives (including anti-oxidants) and the like, and substances included for the purpose of rendering the formulation isotonic with the blood of the intended recipient. The invention will now be illustrated by the following Examples which should in no way be considered as a limitation thereof. EXAMPLE 1 Acute Anti-inflammatory Activity of 3-Deazaadenosine: Carrageenan -Pleurisy Assay (CPA) Following the procedure previously described by Vinegar et al. in Proc. Soc. Exp. Biol. Med., 143, 711, (1973) as recently modified /Vinegar et al., Eur. J. Rheum. Inflamm., 1, 204 (1978)/ the acute anti-inflammatory activity of 3-deazaadenosine was compared with that of known anti-inflammatory drugs. The average 3 hour exudate volume for each drug treated group was determined and the % inhibition relative to solvent-fed control animals calculated, the ED50 (mg/kg body weight) being the dose required to reduce the 3 hour exudate volume by 50%. There were 5 animals in each drug-treated group and the control group. The results are shown in Table 1: TABLE 1 ED50 (mg/kg) EMI8.1 <tb> <SEP> 3-Deazaadenosine <SEP> Aspirin <SEP> Prednisolone <SEP> Hydrocortisone <tb> 3 <SEP> hr. <SEP> vol. <SEP> 2.8+0.65 <SEP> 28+3.2 <SEP> 3+0.50 <SEP> 14+10.2 <tb> p.o. <SEP> <tb> EXAMPLE 2 Duration of Action of Anti-inflammatory Activity of 3-Deazaadenosine By means of the Carrageenan Pleurisy Assay of Example 1 the duration of action of the tests compounds after a single oral pretreating dose was determined. For 3-deazaadenosine the effect lasted for 14.9 hours at 6 mg/kg (p.o.) whilst for aspirin (150 mg/kg p.o.) and acetaminophen (220 mg/kg p.o.) the effect lasted for 35 hours and 2 hours respectively. This value represents the time (hours) of drug administration prior to the injection of carrageenan in which the inhibition of the 3 hour pleural exudate volume declined to 40%. EXAMPLE 3 Local Anti-inflammatory Activity of 3-Deazaadenosine: Carrageenan Pleurisy Assay (CPA) Following the procedure described by Vinegar et al. hour. J. Rheum. Inflamm., 1, 204, (1978)/ the local anti-inflammatory activity of 3-deazaadenosine was determined and compared to that of standard anti-inflammatory drugs. There were 5 animals in each drug-treated group and the control group. The results are shown in Table 2: TABLE 2 - ED50 (mg/kg) EMI9.1 <tb> <SEP> 3-Deazaadenosine <SEP> Hydrocortisone <SEP> Aspirin <tb> 3 <SEP> hr. <SEP> vol. <SEP> local <SEP> 0.05 <SEP> 0.1 <SEP> 0.04 <tb> (intra-pleural) <tb> EXAMPLE 4 Effect of 3-Deazaadenosine against Adjuvant Arthritis The effect of 3-deazaadenosine in rats againt both developing and established adjuvant arthritis was determined by the method described by R. Vinegar et al. Journal of immunopharmacology. 1, 483, (1979). The scoring procedure of A.L.F. Currey and M. Ziff, 3. Exp. Med., 121, 185 (1968) was used to assess the arthritic joint scores of rats. There were 5 animals in each drug-treated group. For developing adjuvant arthritis the drugs were administered in the diet from day 1 to day 16. For established adjuvant arthritis the drugs were administered from day 21 to 42. The results are shown in Table 3 below. TABLE 3 EMI9.2 <tb> rug <SEP> Developing <SEP> Arthritis <SEP> Established <SEP> Arthritis <tb> <SEP> ED50 <SEP> on <SEP> Day <SEP> 16 <SEP> mg/kg/day <SEP> ED25 <SEP> on <SEP> Day <SEP> 42 <tb> <SEP> in <SEP> diet. <SEP> mg/kg <SEP> day <SEP> in <SEP> diet <tb> 3-deazaadenosine <SEP> 8 <SEP> + <SEP> 2.8 <SEP> (18)* <tb> Aspirin <SEP> 150 <SEP> + <SEP> 53.1 <SEP> 150 <tb> Prednisolone <SEP> 1 <SEP> + <SEP> 0.7 <SEP> 0.2 <tb> *Parentheses indicate an approximate value. EXAMPLE 5 Water Soluble Ointment Amount (g) 3-D eazaadenosine 0.5 Polyethylene glycol 300 20.0 Polyethylene glycol 1500 79.5 100.0 EXAMPLE 6 Skin Cream Amount (g) 3-Deazaadenosine 0.5 Glyceryl monostearate 20.0 Methylparben 0.3 Petrolatum light liquid 4.0 Propylene glycol 5.0 Span 60 2.0 Tween 61 4.0 Water 64.6 Total 100.0 EXAMPLE 7 Tablet Formulation Amount per tablet 3-Deazaadenosine 50 mg Lactose 85 mg Potatoe Starch, dried 14.3 mg Magnesium Stearate 0.7 mg Total 150 mg EXAMPLE 8 Syrup Amount per 10 ml 3-Deazaadenosine 10 mg Glycerine 1 mg Sucrose 7g Methyl paraben 10 mg Sodium Benzoate 10 mg Flavour, Cherry 0.01 ml Colouring q.s. Water, purfied q.s. to 10 ml EXAMPLE 9 injection Amount per Ampoule 3-Deazaadenosine 10 mg Sodium Chloride 8.5 mg Water for injection q.s. to 10 ml What we claim may comprise any novel feature disclosed herein, principally but not exclusively for example: (i) a method for the treatment of inflammation in mammals, including humans sufferingh from an inflammatory condition, whcih comprises the administration of an inflammation reducing, non-toxic amount of 3-deazaadenosine or a pharmaceutically acceptable salt thereof; (ii) 4-amino-1-ss-D-ribofuranosyl-1H-imidazo[4,5-c]-pyri dine or a pharmac eutically acceptable salt thereof for use in the treatment of inflam mation; ; (iii) a pharmaceutical formulation, particularly a topical formulation, comprising 4-amino-1 - > B-D-ribofuranosyl-1 H -im idazo-E415--pyridine or a pharmaceutically acceptable salt thereof together with a pharma ceutically acceptable carrier therefor.

Claims: CLAIMS: I. A pharmaceutical formulation adapted for topical application and com prising, as active ingredient, 4-amino-i -B-D-ribofuranosyl-l H-imidazo- 4,5-g7-pyridine or a pharmaceutically acceptable acid addition salt thereof together with a pharmaceutically acceptable carrier therefor. 2. A formulation as claimed in claim 1 in the form of a lotion, jelly, spray, aerosol, ban a oil or ointment. 3. A formulation as claimed in claim 1 or claim 2 in the form of an oint ment. 4. A formulation as claimed in claim 3 in which the ointment has an olea ginous, absorption, water-soluble or emulsion-type base. 5. A formulation as claimed in either of claims 3 or claim 4 in which the base comprises petrolatum, lanolin, polyethylene glycols and mixtures thereof. 6. A formulation as claimed in any of claims 3 to 5 in the form of a cream. 7. A formulation as claimed in any one of claims 1 to 4 in which the con centration of the active ingredient is in the range of from 0.1% to 10% w/w. 8. A formulation as claimed in claim 5 in which the concentration of active ingredient is from 0.2 to 0.5% w/w. 9. 4-Amino-1-ss-D-ribofuranosyl-1H-imidazo-[4,5-c]-pyridine or a pharma ceutically acceptable acid addition salt thereof for use in the treatment of inflammation.

Inventors: VINEGAR, RALPH, WOLBERG, GERALD
Applicants: THE WELLCOME FOUNDATION LIMITED
Application year: 1981
Main classification: A61K31
IPC codes: A61P29, B22D11, C07H19, A61K31