Determination of nifedipine in human serum by gas chromatography—mass spectrometry: validation of the method and its use in bioavailability studies

A procedure for the determination of nifedipine in human serum is described. The light-sensitive substance is isolated from serum by liquid—liquid extraction and analyzed using capillary gas chromatography with a mass-selective detector. The validation of the method shows that the extraction recovery is ca. 85%, the limit of detection is 2 ng/ml and the standard deviations of the intra-day precision test range from 5.8 to 7.4% with respect to the concentration. The procedure is highly selective and sensitive. It is especially suited for bioavailability studies because of its stability and high sampling rate.