Determination of pethidine in rabbit plasma by capillary gas chromatography

A simple and fast gas chromatographic method for the determination of pethidine hydrochloride in rabbit plasma is described and validated. This method is an improvement on the GC method which uses a glass column, and was described previously by Koska et al. [Anaesth. Analg. 60 (1981) 8]. The samples were analysed by a GC 5890 HP system using Rtx-5, fused-silica capillary column linked to a nitrogen-phosphorus ionization detector. Lidocaine hydrochloride was used as the internal standard. Calibration curves were linear within the range 5-200 ng/ml. The limit of quantification was about 5 ng using a 1-ml biological sample and no interference was observed in the blank plasma. The mean recovery of the drug from plasma samples was 95.71+/-2.82%. This procedure turned out to be sensitive and convenient enough for the use in pharmacokinetic studies of pethidine.