Abstract: AIM: To develop a HPLC method for the determination of nifedipine in plasma. METHODS: Nitrendipine was used as the internal standard and 1.0 ml lasma was extracted by n-hexane-ethylacetate (3 ∶1)in a two-step extraction.The organic layer was transferred to another tube and evaporated to dryness under a stream of nitrogen gas at 55 ℃.The residue was reconstituted with the mobile phase. RESULTS: the linearity was obtained from 5 to 200 μg·L^-1 of nifedipine in plasma with a good correlation (r=0.9999, n=6).The recoveries of nifedipine were 90.13% to 99.43%, and the coefficients of variation of within-day and between-days were 1.43% to 6.61% and 3.85% to 8.79%, and the average absolute recoveries of nifedipine and internal standard were 90.58% and 91.59% for the low, middle and high concentration of check samples, respectively.Endogenous substance did not interfere in the analysis. CONCLUSION:~This method is sensitive, specific and simple and suited for the nifedipine pharmacokinetic study.

Key words: pharmacology, nifedipine, plasma concentration, HPLC