Author(s): Ch. S. Vijayavani, Vidyavathi Maravajhala
A simple, accurate, precise, sensitive, and reproducible isocratic high-performance liquid chromatography method was developed for the determination of Nifedipine in rabbit plasma. Liquid–liquid extraction was used as the sample preparation technique. Carbamazepine was employed as an internal standard (IS). Chromatographic separation was achieved on a Phenomenex C18 (5×4.0 mm, 5 μm particle size) column using Shimadzu LC20AT system with LC20AD pump at room temperature in isocratic mode. The column effluent was monitored by UV detector (ultraviolet variable wavelength detector, Model SPD-20A Shimadzu, Japan) at 235nm. The mobile phase used was water: acetonitrile:Triflouro acetic acid in the ratio of 40:60:0.1 (v/v/v ) at a flow-rate of 1.0 mL min 1 . Nominal retention times of Nifidipine and IS were 5.5and 3.8 mins, respectively, with a total run time of 8 min. Method validation was performed according to US Food and Drug Administration bioanalytical guidelines and the results met the acceptance criteria. The calibration curve of Nifidipine in rabbit plasma was linear over the concentration range of 2–1000 ng mL 1 with a regression coefficient of 0.999. The recovery was about 100.5%and the limit of quantitation (LOQ) was 1.36 ng/mL. The LOD was found to be 4.12 ng/mL .Intra- and interrun precisions of Nifidipine at a working concentration of 100ng/mL were exemplified with a % RSD of 0.569 and 0.69% respectively. The method was found to be precise, accurate, robust , rugged and specific during the study and is useful for invivo studies of Nifedipine.