Comparison of stability-indicating assay methods: ultraviolet, high pressure liquid chromatography and acid dye

Three techniques--ultraviolet, high pressure liquid chromatography (HPLC) and acid dye--were compared as stability-indicating assay methods. Investigations on six drugs (codeine phosphate, ephedrine hydrochloride, morphine sulfate, procaine hydrochloride, pyrilamine maleate and thiamine hydrochloride) indicate that HPLC is the most reliable method.