Comparison of a GLC-NPD method with a GLC-MS-SIM procedure for the determination of tilidine and its metabolites in plasma.

A gas liquid chromatographic method with nitrogen-phosphorus detection (GLC-NPD) is compared to a GLC-mass spectrometric determination employing selected ion monitoring (GLC-MS-SIM). These two methods of gas chromatographic separation were shown to be suitable for therapeutic monitoring of tilidine, nortilidine, and bisnortilidine in patients. The pharmacokinetic profile of tilidine was also studied in three normal humans after a single oral dose. Pharmacokinetic parameters such as Cmax, tmax, (t1/2) beta, AUC, AUMC, Vd beta, Cltot, beta, and MRT are derived from model independent pharmacokinetic techniques.