Pharmacokinetics of lansoprazole and its main metabolites after single and multiple intravenous doses in healthy Chinese subjects.

The aim of the study was to evaluate and compare the pharmacokinetics of lansoprazole (LPZ) and its main metabolites, 5'-hydroxy lansoprazole (HLPZ) and lansoprazole sulfone (LPZS), after single and multiple intravenous (i.v.) doses of LPZ in healthy Chinese subjects. Twelve subjects (six males and six females) were given a single dose of LPZ by i.v. infusion on day 1, and multiple doses from day 2 to day 6. Blood samples were collected at designated time points for analysis of plasma concentrations of LPZ, HLPZ and LPZS by an LC-MS/MS method. LPZ was generally well tolerated in healthy Chinese subjects. After single and multiple i.v. doses of 30 mg LPZ, the C max values of LPZ, HLPZ and LPZS were 1490 ± 290 and 1450 ± 280, 175 ± 71 and 154 ± 56, and 51.3 ± 82.9 and 74.1 ± 158.7 ng/mL, with the AUC0-t values 3280 ± 2550 and 4260 ± 3880, 381 ± 128 and 389 ± 111, and 389 ± 1204 and 700 ± 2255 ng h/mL, respectively. The t 1/2 and CL values of LPZ after single and multiple i.v. doses were 1.48 ± 1.03 and 2.19 ± 1.03 h, and 11.67 ± 4.49 and 9.56 ± 4.08 L/h, respectively. Compared with the pharmacokinetics of LPZ after a single dose, t 1/2 increased markedly, CL decreased significantly and AUC increased by over 20 % after multiple doses. The results indicated that there was drug accumulation of LPZ after multiple i.v. doses, and there was no gender-related difference in pharmacokinetics of LPZ and its two metabolites.