Study On The Pharmacokinetics And Bioequivalence Of Lercanidipine Hydrochloride Tablets In Healthy Volunteers

Lercanidipine Hydrochloride , (±)(1,4-dihydro-2,6-dimethyl-4-(3 -nitrophenyl)-3,5-Pyridinedicarboxylic acid [2-[(3,3-diphenylpropyl) methylamine]-l,l-dimethylethyl]methyl ester hydrochloride, is a new dihydropyridine calcium antagonist having longest-last activity. Like other dihydropyridine calcium channel blockers, lercanidipine hydrochloride causes systemic vasodilation by blocking the influx of calcium ions through L-type calcium channels in vascular smooth muscle cell membranes. Due to its high lipophilicity it has a slower onset and longer duration of action than other calcium antagonists of the dihydropyridine type. In addition, lercanidipine hydrochloride has antiatherogenic potential and it may also protect against end organs damage. The plasma concentration of lercanidipine hydrochloride after oral administration in human is very low. Therefore, it is necessary to establish a fast and sensitive analytical method for pharmacokinetic and bioequivalence studies of lercanidipine hydrochloride. In this paper, a sensitive and specific method for determination of lercanidipine hydrochloride in human plasma was established, base on HPLC-MS. The method was successfully used to investigate the pharmacokinetics and bioequivalence of lercanidipine hydrochloride after single oral administration 20mg test and reference tablets in Chinese healthy male volunteers.A sensitive, simple, and accurate HPLC-MS method was established for the determination of lercanidipine hydrochloride in human plasma in the Section 1. The human plasma added internal standard benidipine hydrochloride was extracted by hexane/isopropanol (99:1, v/v), subsequently, the extraction was determined by HPLC-MS. The column was C18 (Phenomenex, 100×2.0mm , 3μm ) , and the precolumn was C18 (Phenomenex,10×2.0 mm,3μm). The mobile phase was 0.50% acetic acid (adjusted to pH 4.50 with ammonia) /methanol with the volume ratio of 15: 85, and the flow rate was 0.20ml per minute. HPLC-ESI-MS was used in the selected positive ion monitoring mode. Linearity was established for the concentration ranges of 0.20ng/mL to 10.0ng/mL with related coefficient 0.9991. The lower limit of quantification was identifiable and reproducible at 0.20ng/mL with signal/noise ratio of 10. The recovery of the method was more than 80%. The RSD of within-day precision and day-to-day precision were lower than 9.7%. A determination of lercanidipine hydrochloride in human plasma by HPLC-MS described in this paper is sensitive, accurate and suitable for therapeutic drug monitoring. It is suitable for pharmacokinetics and bioequivalence study of lercanidipine hydrochloride too.In the Section 2, the main pharmacokinetic parameters of test and reference tablets obtained from 19 Chinese healthy volunteers after single oral administration 20mg test and reference tablets were investigated, and the bioequivalence of two kinds of lercanidipine hydrochloride tablets was evaluated. 19 Chinese healthy male volunteers were randomly divided into two groups, in cross-over and two period design test. The concentrations in human plasma of 19 Chinese healthy male volunteers after single oral administration 20mg test and reference tablets were determined by the HPLC-MS method established in the Section 1. The results showed that the main pharmacokinetic parameters of test and reference tablets obtained from 19 Chinese healthy volunteers after single oral administration 20mg test and reference tablets were as follow: AUC_0-t were(16.8±4.5)ng·h·mL^-1and(17.0±5.2)ng·h/mL, AUC_0-∞ were(18.8±4.6)ng·h/mLand(19.0±5.4)ng·h/mL, Cmax were(4.5±0.9)ng/mL and(4.5±0.8)ng/mL, T_max were(1.76±0.34)h and(1.87±0.40)h, t_1/2 were(4.07±1.32)h and(4.06±1.09)h,the relative bioavailability of lercanidipine hydrochloride test tablets was (100.8±10.1)%. According to the Guidance Principle for Bioavailability and Bioequivalence of Studying Chemical Formulations in the Human Body( 2005 ) , pharmacokinetic parameters (AUC_0-t,Cmax and T_max)were indicators to evaluate the bioequivalence of the drugs. The pharmacokinetic parameters AUC_0-t and Cmax of lercanidipine hydrochloride test and reference tablets were evaluated the bioequivalence after logarithm transformation. ANOVA analysis and two one-sided t-test showed that no significant difference existed in the pharmacokinetics parameters AUC0-t and Cmax between test and reference tablets. 90% confidence interval for test formulation/ reference formulation ratios of AUC0-t were found within the bioequivalence acceptance range of 80%～125%. 90% confidence intervals for test formulation/ reference formulation ratios of Cmax were found within the bioequivalence acceptance range of 70%～143%. Wilcoxon test showed that no significant difference existed in the T_max between test and reference tablets. Lercanidipine hydrochloride test formulation and reference formulation were bioequivalence in healthy human.