Quantification of prochlorperazine maleate in human plasma by liquid chromatography–mass spectrometry: Application to a bioequivalence study

A sensitive and specific method using a one-step liquid–liquid extraction with dichloromethane followed by liquid chromatographic–electrospray ionization-mass spectrometric was developed and validated to determine prochlorperazine maleate in human plasma using amitriptyline hydrochloride as an internal standard. The samples were separated using a Thermo Hypersil-Hypurity C18 reversed-phase column (150 mm × 2.1 mm i.d., 5 μm). A mobile phase containing 10 mM ammonium acetate (pH 3.6)–methanol–acetonitrile (27:68:5, v/v/v) was used isocratically eluting at a flow rate of 0.22 ml/min. The average extraction recovery of prochlorperazine and internal standard were 81.8 ± 2.2% and 79.5 ± 3.7%, respectively. Prochlorperazine maleate and internal standard were measured by electrospray ion source in positive selective ion monitoring mode. The method demonstrated that good linearity ranged from 0.20 to 6.40 ng/ml with r2 = 0.9989. The limit of quantification for prochlorperazine maleate in the plasma was 0.20 ng/ml. The established method has been successfully applied to a bioequivalence study of two prochlorperazine maleate formulations in 18 healthy male Chinese volunteers.