Sensitive and Rapid Quantification of Felodipine by High-performance Liquid Chromatography-tandem Mass Spectrometry (HPLC-MS/MS) and Its Pharmacokinetics in Healthy Chinese Volunteers1

To investigate the pharmacokinetics of felodipine in the plasma of healthy Chinese volunteers, 30 healthy volunteers received a single oral dose of 5 mg of extended release felodipine tablets. The felodipine was extracted from the matrix with a liquid-liquid extract procedure and analyzed by high-performance liquid chromatography-tandem mass spectrometry in the multiple reaction monitoring(MRM) mode using an electrospray ion source with positive ion detection. The method was validated over a felodipine concentration range of 0.05-10.00 ng/mL in human plasma. Its main pharmacokinetic parameters values were; ρmax = (1.67 ± 0.84) ng/mL, occurring at (3.93 ± 2.49) h; the plasma elimination half-life; (23.08 ± 9.48) h and the area under the plasma concentration versus time curve: (29.94 ± 14.39) ng h/mL. The validation results demonstrated that this method showed a satisfactory precision and accuracy across the calibration range. The procedure involved minimal drug administration, sample preparation, and a 2.5-min chromatographic run time. It was well suited to clinical studies of the drug involving large numbers of samples.