High pressure liquid chromatographic determination of nitrendipine in human plasma after solid phase extraction

A rapid and sensitive Reversed-Phase High Pressure Liquid Chromatographic ( RP-HPLC) method has been developed for the quantitative determination of ni trendipine in human plasma. A Hypersil C-18 150x4.6 mm, 5 mu m analytical column was used with a mixtur e of CH3CN-H2O at a volume ratio 50:50 v/v. Detection was performed with a variable wavelength UV-VIS detector at 238 nm. The detection limit was 0.4 ng/mL. Nimodipine was used as internal standard (IS) at concentration of 12 ng/mL. The statistical evaluation of the method was examined performing intra-day and inter-day calibration. Nitrendipine was extracted from human plasma matrices by Solid Phase Extrac tion (SPE) technique instead of conventional liquid-liquid extraction metho ds. Recovery of nitrendipine in spiked samples was 97.75+/-5.43. The method was applied to a preliminary pharmacokinetic study in which an o ral dose of 20 mg of nitrendipine was given to eight healthy volunteers.