title: Determination of nifedipine in human plasma and its use in bioequivalence study.
abstract: A sensitive atmospheric pressure chemical ionization liquid chromatographic-mass spectrometric (APCI-LC-MS) assay with positive ion mode has been developed for the determination of nifedipine in human plasma. In this method, nifedipine was extracted from human plasma using diethyl ether with dimethoxanate as the internal standard. Analysis was achieved on a BDS C(18) column with methanol-H(2)O (66:34, v/v) as the mobile phase. Sustained-release nifedipine tablets from DiSha (test, Weihai, China) and from GuoFeng (reference, Qingdao, China) were evaluated following a single 20mg oral dose to 20 healthy volunteers. Bioequivalence between the products was determined by calculating 90% confidence intervals (90% CI) for the ratio of C(max), AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The 90% confidence intervals for the ratio of C(max) (86.6-105.2%), AUC(0-t) (97.8-110.9%) and AUC(0-infinity) (96.5-110.4%) values for the test and reference products are within the interval (80.0-125.0% for AUC, and 70-143% for C(max)), proposed by State of Food and Drug Administration [SFDA, 2005. Guidance for Bioavailability and Bioequivalence Studies for Chemical Drug Products in Human Being. China, p. 19]. It was concluded that the two sustained-release nifedipine tablets are bioequivalent in their rate and extent of absorption and, thus, may be used interchangeably.
authors.affiliation: School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China.
authors.forename: Yunzhen
authors.initials: Y
authors.lastname: Guo
authors.forename: Jinna
authors.initials: J
authors.lastname: Dai
authors.forename: Guiling
authors.initials: G
authors.lastname: Qian
authors.forename: Na
authors.initials: N
authors.lastname: Guo
authors.forename: Zheng
authors.initials: Z
authors.lastname: Ma
authors.forename: Xingjie
authors.initials: X
authors.lastname: Guo
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D009543:Nifedipine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D012016:Reference Values; D015203:Reproducibility of Results; D013810:Therapeutic Equivalency
chemical_list: D002121:Calcium Channel Blockers; D003692:Delayed-Action Preparations; D009543:Nifedipine