AIMTo establish a method for determinate of the inhibitory activity of angiotensin-converting enzyme inhibitor captopril by high performance capillary electrophoresis.

METHODSThe characteristic absorptive wavelength of hippuric acid determined by ultraviolet spectrophotometer is 228 nm. The method employed a melted capillary column, 50 mmol.L-1 phosphoric acid (pH 8.3) buffer solution, inject pressure 4.8 kPa, inject time 3 s, separation voltage 20 kV and detection wavelength 228 nm.

RESULTSThe reactant and resultant was separated completed within 7 min. IC50 of captopril was 0.019 mumol.L-1. Captopril is a competitive inhibitor, which was proved by enzyme reaction dynamics.

CONCLUSIONThe method was shown to be accurate, simple and rapid and can be used for determination of the inhibitory activity of captopril.