Internally standardized method for the determination of nalbuphine in human plasma by means of high performance liquid chromatography with electrochemical coulometric detection.

A high performance liquid chromatographic method with internal analogue standardization and electrochemical detection for the determination of nalbuphine in human plasma is described. Using 3 ml plasma the lower limit of detection is below 50 pg/ml, during the routine assay the limit of determination can be fixed at about 250-300 pg/ml. The calibration curve is linear in the range between 0.163-65 ng/l, the recovery rate from plasma exceeds 80%. The method was successfully applied in several pharmacokinetic studies.