HPLC method for the simultaneous determination of pilocarpine, isopilocarpine, pilocarpic acid and isopilocarpic acid.

A high-performance liquid chromatographic method suitable for the determination of pilocarpine, isopilocarpine, pilocarpic acid and isopilocarpic acid is described. The column used is a Spherisorb-CN bonded phase at 25 degrees C. An aqueous solution of triethylamine (0.1%, v/v) at pH 2.5 is used as mobile phase. Peak detection is by UV absorption at 220 nm. The elution orders are found to be pilocarpic-isopilocarpic acids with a resolution of 9 and K' of 5 and 6, respectively, isopilocarpine-pilocarpine with a resolution of 1.8 and K' of 13 and 13.5, respectively, the peaks being symmetrical.