Method of preparing a controlled-release pharmaceutical preparation, and resulting composition

Claim 1

In a method for preparing a controlled-release pharmaceutical composition for oral administration, the method which comprises: forming an aqueous emulsion of phospholipid encapsulating agent with the pharmaceutical compound whose release is to be controlled; coagulating the emulsion to entrap the pharmaceutical compound within the phospholipid agent; and recovering the pharmaceutical composition as prepared, the improvement which comprises: employing as the phospholipid encapsulating agent a synthetic fatty-acid phosphatidyl .[.C 1 -C 10 alkyl-N-C 1 -C 4 trialkyl.]. quaternary-ammonium hydroxide compound.[., with the proviso that the alkyl of the alkyl-N group is not an ethyl group when the alkyl groups of the N-trialkyl radicals are methyl groups.]. .Iadd.represented by the structural formula: .Iaddend. ##STR2## .Iadd.wherein R 4 is a C 1 -C 10 methylene radical and R 1 , R 2 and R 3 are C 1 -C 4 alkyl radicals, with the proviso that R 1 , R 2 and R 3 at the same time are not all methyl radicals and wherein R is a fatty-acid radical.Iaddend., and which phosphatidyl quaternary-ammonium compound is resistant to enzymatic hydrolysis of phospholipase C.