title: In vivo evaluation of two novel controlled-release nitrendipine formulations.
abstract: The objective of this work is to assess two novel controlled-release nitrendipine formulations, i.e., sustained-release nitrendipine microspheres having solid dispersion structure and a novel pH-dependent gradient-release delivery system for nitrendipine in healthy male volunteers, which were prepared by current authors. Domestic commercial nitrendipine tablets and Baypress nitrendipine tablets were employed as reference formulations. In a randomized, single-dose, fasting-state, crossover study design with a 1-week washout period, each subject received a 40-mg nitrendipine formulation. Plasma samples were collected over a 25-hour period after oral administration and were analyzed by a validated method using high performance liquid chromatography with ultraviolet detection. Pharmacokinetic parameters were determined using a noncompartmental analysis. The results provided evidence that the time to maximum plasma concentration of two novel controlled-release nitrendipine formulations were statistically significant prolonged in comparison with that of Baypress nitrendipine tablets. The relative bioavailabilities of test formulations were intensively improved compared with the domestic nitrendipine tablets, while the ratio is in a range of 80-120% in comparison with Baypress nitrendipine tablets. It is concluded that the two types of controlled-release systems are feasible for improving the dissolution rate of nitrendipine and obtaining a long-acting in vivo as well.
authors.affiliation: Department of Pharmaceutics, School of Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang, China [corrected]
authors.forename: Mingshi
authors.initials: M
authors.lastname: Yang
authors.forename: Fude
authors.initials: F
authors.lastname: Cui
authors.forename: Bengang
authors.initials: B
authors.lastname: You
authors.forename: Minghua
authors.initials: M
authors.lastname: Yang
authors.forename: Anjin
authors.initials: A
authors.lastname: Tao
authors.forename: Dongmei
authors.initials: D
authors.lastname: Cun
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawashima
mesh_terms: D001682:Biological Availability; D002121:Calcium Channel Blockers / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D006801:Humans; D008297:Male; D008863:Microspheres; D009568:Nitrendipine / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D002121:Calcium Channel Blockers; D003692:Delayed-Action Preparations; D009568:Nitrendipine