High-performance liquid chromatographic analysis of pilocarpine hydrochloride, isopilocarpine, pilocarpic acid and isopilocarpic acid in eye-drop preparations.

A high-performance liquid chromatographic method is described which allows the simultaneous estimation of pilocarpine, isopilocarpine, pilocarpic acid and isopilocarpic acid. The method offers advantages over existing chromatographic procedures in that pilocarpine and the degradation products are eluted within 15 min making the procedure suitable for routine quality control. Pilocarpine eye-drop preparations available on the Australian market were determined to contain between 0.4 and 1.9% isopilocarpine and between 2.2 and 6.3% total pilocarpic acids. These findings are comparable to those reported by Weber in a survey of pilocarpine containing products available in the U.S.A.