Compositions Containing Benzoylacetonitrile and Method of Use to Treat Inflammation

This invention relates to novel compositions of matter useful as anti-inflammatory agents and as inhibitors of the progressive joint deterioration characteristic of arthritic disease. More particularly, it relates to therapeutic compositions containing benzoylacetonitrile, o-fluorobenzoylacetonitrile, m-fluorobenzoylacetonitrile, p-fluorobenzoylacetonitrile, or mixtures thereof which meliorate inflammation and inhibit arthritic joint deterioration in mammals. The invention includes the new compositions of matter and the methods of meliorating inflammation and of inhibiting joint deterioration in mammals therewith. Benzoylacetonitrile and o-fluorobenzoylacetonitrile have been described by Dorsch et al., J.A.C.S. 54, 2960 (1932) and by Nakanishi et al., J. Med. Chem., 16(3), 214 (1973), respectively; whereas m-fluorobenzoylacetonitrile and p-fluorobenzoylacetonitrile have both been described by Pihl et al., Reakts. Sposobnost Org. Soedin. Tartu. Gos. Univ., 5(1), 27 (1968).

Benzoylacetonitrile, o-fluorobenzoylacetonitrile, m-fluorobenzoylacetonitrile, and p-fluorobenzoylacetonitrile have been found to be highly useful for meliorating inflammation and inhibiting joint deterioration in mammals when administered in amounts ranging from about one milligram to about 250 mg. per kilogram of body weight per day. A preferred dosage regimen for optimum results would be from about 5 mg. to about 100 mg. per kilogram of body weight per day, and such dosage units are employed that a total of from about 0.35 gram to about 7.0 grams of the active ingredient for a subject of about 70 kg. of body weight are administered in a 24 hour period. This dosage regimen may be adjusted to provide the optimum thereapeutic response. For example, several divided doses may be administered daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation. A decided practical advantage of this invention is that the active ingredient may be administered in any convenient manner such as by the oral, intravenous, intramuscular, topical, or subcutaneous routes.

Compositions according to the present invention having the desired clarity, stability and adaptability for parenteral use are obtained by dissolving from 0.10% to 10.0% by weight of active compound in a vehicle consisting of a polyhydric aliphatic alcohol or mixtures thereof. Especially satisfactory are glycerin, propylene glycol, and polyethylene glycols. The polyethylene glycols consist of a mixture of non-volatile, normally liquid, polyethylene glycols which are soluble in both water and organic liquids and which have molecular weights of from about 200 to 1500. Although the amount of active compound dissolved in the above vehicle may vary from 0.10 to 10.0% by weight, it is preferred that the amount of active compound employed be from about 3.0 to about 9.0% by weight. Although various mixtures of the aforementioned non-volatile polyethylene glycols may be employed, it is preferred to use a mixture having an average molecular weight of from about 200 to about 400.

In addition to the active compound, the parenteral solutions may also contain various preservatives which may be used to prevent bacterial and fungal contamination. The preservatives which may be used for these purposes are, for example, myristyl-gamma-picolinium chloride, phenyl mercuric nitrate, benzoalkonium chloride, phenethyl alcohol, p-chlorophenyl-.alpha.-glycerol ether, methyl and propyl parabens, and thimerosal. As a practical matter it is also convenient to employ antioxidants. Suitable antioxidants include, for example, sodium bisulfite, sodium metabisulfite, and sodium formaldehyde sulfoxylate. Generally, from about 0.05 to about 0.2% concentrations of antioxidant are employed.

For intramuscular injection, the preferred concentration of active compound is 0.25 to 0.50 mg./ml. of the finished compositions. The active compounds are equally adapted to intravenous administration when diluted with water or diluents employed in intravenous therapy such as isotonic glucose in appropriate quantities. For intravenous use, initial concentrations down to about 0.05 to 0.25 mg./ml. of active compound are satisfactory.

The active compound of the present invention may be orally administered, for example, with an inert diluent or with an assimilable edible carrier, or they may be enclosed in hard or soft shell gelatin capsules, or they may be compressed into tablets, or they may be incorporated directly with the food of the diet. For oral therapeutic administration, the active compounds may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Such compositions and preparations should contain at least 0.1% of active compound. The percentage of the compositions and preparations may, of course, be varied and may conveniently be between about 2 to about 60% of the weight of the unit. The amount of active ingredient in such therapeutically useful compositions is such that a suitable dosage will be obtained. Preferred compositions or preparations according to the present invention are prepared so that an oral dosage unit form contains between about 50 and 250 milligrams of active compound.

The tablets, troches, pills, capsules and the like may also contain the following: a binder such as gum tragacanth, acacia, corn starch or gelatin; excipients such as dicalcium phosphate,; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, lactose or saccharin may be added or a flavoring agent such as peppermint, oil of wintergreen, or cherry flavoring. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier such as a fatty oil. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit. For instance, tablets, pills, or capsules may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavoring such as cherry or orange flavor. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed.

The following test shows the activity of the active compounds against chronic inflammation in adjuvant induced arthritis which is accompanied by joint destruction. Groups of three royal Hart, Wistar strain rats weighing 200+10 grams each were injected intradermally in the right hind paw with Freund's adjuvant (dried human tubercle bacilli in a mineral oil vehicle) at a dose of 2 mg./kg. of body weight. Test compounds were administered orally in a 1.5% starch vehicle at various doses once daily on days 0 through 13 post challenge. Control rats were treated in a similar manner, but given only starch vehicle. On the 14th and 21st day post challenge the diameter of the injected paw (primary lesion) was measured by micrometer caliper. The volume of inflamed paws were estimated from these measurements and the results are expressed as percent inhibition of swelling as compared to controls. At the same time, the other inflamed sites, such as ears, paws and tail (secondary lesions) were observed and each rat was graded as to degree of inflammation and swelling present. The grading is based on a scale of 0 to 24, where 0 represents a complete absence of induced arthritic nodules and 24 represents the maximum degree of inflammation. The mean grade for each treated group is calculated and the effects of each compound are expressed as percent inhibition of the control grade. Table I records the results of these tests conducted with benzoylacetonitrile, o-fluorobenzoylacetonitrile, m-fluorobenzoylacetonitrile, p-fluorobenzoylacetonitrile, and known anti-inflammatory agents. The active compounds of the present invention suppress the progression of the arthritis and associated joint deterioration.

The invention will be described in greater detail in conjunction with the following specific examples.

The benzoylacetonitrile, lactose and corn starch (for mix) are blended together. The corn starch (for paste) is suspended in 600 ml. of water and heated with stirring to form a paste. This paste is then used to granulate the mixed powders. Additionally water is used if necessary. The wet granules are passed through a No. 8 hand screen and dried at 120.degree. F. The dry granules are then passed through a No. 16 screen. The mixture is lubricated with 1% magnesium stearate and compressed into tablets in a suitable tableting machine.

The sorbitol solution is added to 40 ml. of distilled water and the o-fluorobenzoylacetonitrile is suspended therein. The saccharin, sodium benzoate, flavor and dye are added and dissolved. The volume is adjusted to 100 ml. with distilled water. Each ml. of syrup contains 5 mg. of o-fluorobenzoylacetonitrile.

In a solution of 700 ml. of propylene glycol and 200 ml. of water for injection is suspended 20.0 grams of m-fluorobenzoylacetonitrile with stirring. After suspension is complete, the pH is adjusted to 5.5 with hydrochloric acid and the volume is made up to 1000 ml. with water for injection. The formulation is sterilized, filled into 5.0 ml. ampoules each containing 2.0 ml. (representing 40 mg. of drug) and sealed under nitrogen.

The ethoxylated stearyl alcohol and isopropyl palmitate are heated to liquifying temperature. About 95% of the total volume of water is placed in a separate container followed by the glycerin and sorbitol solution. This aqueous mixture is brought to a boil and then cooled to 60.degree.-75.degree. C. The p-fluorobenzoylacetonitrile is added to the wax phase and the mixture is stirred until a clear solution is obtained. The benzyl alcohol is added and dissolved in the wax phase. The water phase is passed through a screen into the wax phase while maintaining agitation. Both phases are kept at about the same temperature during transfer. The mixture is cooled while agitation is continued. At a temperature of 50.degree.-55.degree. C. the balance of the water is added. The pH is adjusted to 4.0-5.0 with lactic acid. The batch is cooled with minimum agitation until the cream sets in its final form.