Development and validation of a high-throughput method for the quantitative analysis of felodipine in human plasma using high-performance liquid chromatography with mass/mass spectrometer and its application to a bioequivalence study in healthy male Korean subjects

Abstract

A rapid, sensitive, robust and specific method for the determination of felodipine in human plasma was developed using a high-performance liquid chromatography with a tandem mass spectrometer (HPLC–MS/MS) employing amlodipine as an internal standard. Felodipine was extracted from 0.5 mL human plasma using a liquid–liquid extraction procedure using methyl t-butyl ether. The method included a chromatographic run of 2 min using a C18 analytical column (3.0 mm, i.d. × 75 mm, l; particle size, 3.5 μm) and the calibration curve was linear over the concentration ranges from 0.1 to 20 ng/mL (R2 > 0.99). This method had acceptable precision and accuracy, good recovery from the plasma matrix, and stability during the analytical procedures. When the validated method was applied to the bioequivalence study of two felodipine tablet formulations in 30 healthy male Korean subjects, the results were appropriate: no statistically significant difference was observed between the logarithmic transformed area under the curve and maximum plasma concentration (Cmax) values of the two formulations. The 90 % confidence intervals for the ratio of the above mentioned two parameters were within the bioequivalence limit of 0.80–1.25. These results suggested that the HPLC–MS/MS analysis method developed was suitable for the felodipine analysis in human plasma.