Determination of naftopidil enantiomers in rat plasma using chiral solid phases and pre-column derivatization high-performance liquid chromatography

► We developed two chiral RP-HPLC methods to quantify naftopidil enantiomers in plasma. ► Both of the methods were validated and met the demands of bioanalysis. ► The CSPs method was more suitable for pharmacokinetics study of (+)- and (−)-NAF. ► We determined (+)- and (−)-NAF after intravenous injection of (±)-NAF by CSPs HPLC. Two bioanalytical HPLC methods (chiral solid phases (CSPs) HPLC and pre-column derivatization HPLC) were developed and validated for the determination of naftopidil enantiomers in rat plasma. Analytes were extracted from biomaterials by liquid–liquid extraction. The pre-column derivatization HPLC method employed (+)-diacetyl-l-tartaric anhydride (DATAN) as the pre-column derivatization reagent, and subsequent separation of diastereomers was conducted on an Agilent Hypersil ODS column with a mixture of methanol–acetonitrile–phosphate buffer (pH 4.1; 20mM) (40:30:30, v/v/v) flowing at 1mL/min as the mobile phase. The CSPs HPLC method utilized a Chiralpak IA column with a mobile phase of methanol–acetonitrile–acetate buffer (pH 5.3; 5mM) (50:25:25, v/v/v) flowing at 0.5mL/min. In both methods, the analytes were monitored using a fluorescence detector with an excitation wavelength of 290nm and an emission wavelength of 340nm. Both methods were consistent (RSD