Absorbable pharmaceutical compositions based on isomorphic copolyoxalates

Claim 1

In a pharmaceutical depot composition for parenteral administration of effective amounts of a drug released slowly over an extended period of time which comprises a combination of (a) from 1 percent to 99 percent by weight of composition of a drug in an effective depot amount greater than the single dose amount, and (b) a solid, absorbable polymer which is nonreactive toward body tissue and which undergoes biodegradation in the presence of body fluids into products which are metabolized or excreted by the body without adverse body reaction, the improvement comprising employing as said absorbable polymer isomorphic polyoxalate polymers comprising units of cyclic and linear oxalates and having the general formula ##STR2## wherein each R is --(CH.sub.2).sub.n -- A -- (CH.sub.2).sub.n -- I or --(CH.sub.2)--.sub. 4+2n II and from about 5 to 95 mole percent of the R units are I; A is trans 1,4-cyclohexylene or p-phenylene, n is 1 or 2 and is the same for I and II, and x is the degree of polymerization resulting in a polymer having an inherent viscosity of at least 0.20 determined at 25° C. in a 0.1 g/dl solution of polymer in chloroform or hexafluoroisopropanol.