Determination of captopril in biological fluids by gas-liquid chromatography

The quantitation of captopril in biological fluids by gas-liquid chromatography using a flame photometric detector is described. Captopril was converted into an adduct with N-ethylmaleimide and then into the hexafluoroisopropyl ester. The latter derivative was separated on a 2% OV-210 column and determined by employing the captopril-N-hexylmaleimide adduct as an internal standard. The blood level and urinary excretion of captopril administered intravenously to dogs were measured by the proposed method.