Simultaneous determination of propranolol or metoprolol in the presence of butyrophenones in human plasma by gas chromatography with mass spectrometry.

A method has been developed for the simultaneous gas chromatographic determination of propranolol or metoprolol and butyrophenones butyrophenones in human plasma in vitro. The drugs were extracted from plasma by solid-phase extraction. Calibration graphs were linear in the 50-300-ng/mL range. The recovery of the compounds was 80-90%. The sensitivity of the method was adequate for the determination of the drugs at toxic concentrations and at therapeutic levels. It is a simple, rapid, and reproducible method for the simultaneous determination of propranolol or metoprolol and some butyrophenones. The minimum detectable concentration was 50 ng/mL with a flame ionization detector and 10 ng/mL with a mass spectrometer detector.