Pharmaceutical Compositions With Codeine

This invention relates to novel pharmaceutical compositions. More particularly this invention relates to novel therapeutic compositions capable of relieving pain, muscle spasm and limited mobility associated with acute painful muscoloskeletal conditions in warm-blooded animals.

Specifically this invention relates to a therapeutic composition comprising:

a. N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamates having structure: ##STR1## wherein R is selected from the group consisting of methyl and ethyl, R' is selected from the group consisting of ethyl, propyly, isopropyl, butyl and isobutyl and X is selected from the group consisting of ethyl, propyl, isopropyl, butyl, isobutyl and allyl;

b. aspirin; and

c. codeine phosphate.

The N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamates, particularly the N-isopropyl-2-methyyl-2-propyl-1, 3-propanediol dicarbamate known as carisoprodol are disclosed in U.S. Pat. No. 2,937,119 and are colorless liquids of high boiling point or low melting solids. They are soluble in most organic solvents but only slightly soluble in water at room temperature. The N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamates possess strong muscle relaxant activity. The N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamates, particularly carisoprodol are centrally-acting muscle relaxants that do not directly relax the tense skeletal muscles in warm-blooded animals. In animal studies carisoprodol has been shown to produce muscle relaxation by blocking interneuronal activity and depressing the transmission of polysynaptic neurons in the spinal cord and in the decending reticular formation of the brain.

In man, the mode of action of carisoprodol has not been clearly identified but is believed to be related to its sedative properties. When ingested in tablet form, the onset of the muscle relaxant properties of the N-mono-substituted-2, 2-dialkyl-1, 3-propanediol dicarbamates is rapid and its effects last for from four to six hours.

Aspirin chemically described as 2-(acetyloxy) benzoic acid or salicylic acid acetate or acetylsaliicylcic acid is a non-narcotic analgesic having anti-flammatory and antipyretic activity. Aspirin is the standard non-narcotic analgesic against which all other non-narcotic analgesics are judged. It is believed that inhibition of prostaglandin biosynthesis accounts for most of aspirin's anti-inflammatory activity and for at least part of its analgesic and antipyretic properties. Aspirin is rapidly absorbed when orally administered and is almost totally hydrolyzed to salicyclic acid which has a biologic half-life in the therapeutic plasma concentration range of between six and twelve hours.

Codeine phosphate is a centrally-acting narcotic-analgesic. It is the most important alkaloid of opium and is usually prepared from morphine. Codeine phosphate actions are qualitatively similat to morphine, but its potency is substantially less.

Clinical studies by Saul S. Bloomfield, M.D. reported in NESA Proceedings, Spring 1981, Vol. 2, No. 2, pp. 72-78, have shown that combining aspirin and codeine produces significant synergistic effect in analgesic efficacy.

It has now been found that the therapeutic composition comprising the combination of an N-monosubstituted-2, 2-dialyyl-1, 3-propanediol dicarbamate, aspirin and codeine phosphate when administered to warm-blooded animals gives relief from paim, muscle spasm and impaired mobility associated with acute muscoloskeletal conditions superior to the effects obtained using the active components separately or from a consideration of the activities of the components of the composition as disclosed in the prior art.

In its broad aspect, the present invention relates to a composition containing a N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamate in combination with aspirin and codeine phosphate.

In a more particular aspect, this invention relates to pharmaceutical compositions, in suitable oral dosage forms, containing specific ratios of N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamate, aspirin and codeine phosphate.

In a further aspect, this invention relates to the use of such compositions for the systematic treatment and control of pain, muscle spasm and limited mobility associated with acute painful muscoloskeletal conditions.

The ratios in which the therapeutically active components are embodied in the preparations of this invention may be varied within rather wide limits. For example, the compositions may contain from about 10-15 parts by weight of an N-monosubstituted-2, 2-dialkyl-1, 3-propanediol dicarbamate and from about 15-20 parts by weight aspirin to one or more parts by weight of codeine phosphate. The preferred compositions contain approximately 16 parts by weight aspirin, 10 parts by weight N-isopropyl-2-methyl-1, 2-propyl-1, 3-propanediol dicarbamate per part by weight codeine phosphate.

For administration, this compositions of the invention can be prepared in any of the standard unit dosage forms. Oral administration by the use of tablets and capsules is preferred. Said compositions are prepared in a conventional manner by the addition of suitable pharmaceutical carriers including fillers, diluents, lubricants and the like. When prepared in tablet form, the conventional binding and disintegrating agents are employed. Additional active ingredients compatible with codeine, aspirin and propanediol dicarbamate such as appropriate stimulants, sedatives or the like, to add other desirable properties to said compositions. The incorporation of said additives broadens the area of therapeutic utility of the present compositions, making them especially useful in particular cases where, in addition to anti-inflammatory, analgesic and antipyretic activity, other beneficial effects, such as stimulation, sedation, or the like, are desired.

The example which follows is illustrative of a typical composition of the present invention prepared by conventional well known tabletting techniques such as those disclosed in U.S. Pat. Nos. 3,018,221; 2,798,024 and 2,757,124 as a two-layered tablet for oral administration.