Abstract: A simple and sensitive HPLC method for the determination of drotaverine in human plasma has been developed. Drotaverine in alkalinized plasma was extracted with aether solvent and the drotaverine in the aether phase was back-extracted into 0.1 mol/L HCl. 10μL of the aqueous layer was injected into the C18-column and the eluent was monitored at 254 nm. Separation was performed on the column with 0.02 mol/L sodium dihydrogen phosphate-methanol(30∶70)containing perchlorate at pH 2.8 as mobile phase. Drotaverine was well resolved from the plasma constituents and internal standard. An excellent linearity was observed between peak-height ratios and plasma concentrations and the RSD was always <15%. The lowest limit of detection(signal-to-noise ratio 3∶1)was 8 μg/L, the recovery rate was between 80%～100%. The method is suitable for therapeutic monitoring and pharmacokinetic studies of drotaverine in humans.

Key words: drotaverine, HPLC, human plasma