[Determination of nifedipine and its metabolites in plasma using gas chromatography]

Abstract

A method was worked out to determine nifedipine and its metabolite in plasma with the use of the packed chromatographic column 3% OV-101 and the detector of electron capture. The adjustment od plasma is simple. It consists in denaturation of plasma proteins and subsequent simple extraction with benzene. Denaturation of proteins present in canine plasma is carried out with methanol, where as denaturation of human plasma with ammonium phosphomolybdate. The minimal detectable amount of nifedipine is 0.5 ng.ml-1 of plasma and that of its metabolite, 0.1 ng.ml-1 of plasma. As nifedipine is unstable in daylight, the whole extraction of plasma including the withdrawal of blood must be performed in yellow light. At -18 degrees C and in darkness, nifedipine samples in plasma can be kept for 30 days.