RAPID AND SIMPLE METHOD FOR THE DETERMINATION OF ZOLPIDEM IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A simple and reproducible method for the determination of zolpidem in human plasma is presented. This method involves protein precipitation with methanol (2 ml of methanol are added to 0.5 ml of plasma) and rev ersed-phase chromatography with fluorescence detection (excitation wav elength 244 nm, emission wavelength 388 nm). The mobile phase consists of methanol-30 mM dihydrogen potassium phosphate-triethylamine (30:69 :1). pH of the aqueous part of the mobile phase is 6.8. No internal st andard is required. Limit of quantitation is 1.5 ng/ml and the calibra tion curve is linear up to 400 ng/ml. Within-day and between-day preci sion expressed by relative standard deviation is less than 5% and inac curacy also does not exceed 9%. The assay is useful for pharmacokineti c studies. (C) 1997 Elsevier Science B.V.