Decomposition of aminophylline in suppository formulations.

An aminophylline suppository product, when stored at room temperature, was found to be deficient in ethylenediamine content by the USP XIX assay and by a specific method for primary amines. The product also had a melting point that was considerably higher than body temperature. An accelerated decomposition experiment, conducted on normal suppositories of identical original composition, yielded a product refractory at steam bath temperatures and containing no ethylenediamine measurable by the USP assay. The suppositories from both the original sample and the decomposition experiment contained considerable amounts of a white material, which melted at similar to or approximately 150 degrees and which consisted of the diamide products formed by the reaction of ethylenediamine and the fatty acids present in coconut and palm kernel oils. The results, which confirmed the work of Cieszynski, showed that the ethylenediamine constituent of aminophylline can react with suppository base materials to produce insoluble amide decomposition products.