Objective: The purpose of the study was to evaluate the pharmacokinetics and bioequivalence of pregabalin following administration of a 150-mg capsule of test and reference products.
Method: The study was designed as a randomized, two-treatment, two-period, two-sequence, single-dose crossover with 1-week washout period between period I and period II dosing. 20 healthy male and female Thai subjects were enrolled in the study. Each subject was in fasted state for ~ 10 hours prior to receiving a single oral 150-mg pregabalin capsule. Serial blood samples were collected at pre-dose until 32 hours after drug administration. Plasma samples were extracted by protein precipitation and derivatized with 4-chloro-7-nitrobenzofurazan. Pregabalin plasma concentrations were determined by HPLC method, and pharmacokinetic parameters were calculated. For bioequivalence assessment, the differences of Cmax, AUC0-t, and AUC0-inf means based on ln-transformed data were assessed by the 90% confidence interval (CI).
Results: Pharmacokinetic parameters were determined that test and reference products showed 0.96 ± 0.35 and 1.04 ± 0.96 hours for tmax, 4,594.217 ± 834.195 and 4,568.68 ± 573.963 ng/mL for Cmax, 30,048.150 ± 2,998.920 and 29,315.722 ± 2,747.396 ng×h/mL for AUC0-t, 30,594.210 ± 2,872.317 and 29,831.454 ± 2,688.020 ng×h/mL for AUC0-inf, respectively. The 90% CIs of Cmax, AUC0-t, and AUC0-inf for test and reference products were assessed at 95.356 - 104.630%, 99.303 - 105.751%, and 99.373 - 105.788%, respectively. The results were within the acceptance criteria of 80 - 125%.
Conclusion: Pharmacokinetic parameters of a single oral 150-mg pregabalin capsule in healthy Thai subjects were evaluated and showed rapid absorption. 90% CI for the differences of Cmax, AUC0-t, and AUC0-inf were within the acceptable range of the criteria so that bioequivalence of the test and reference products of pregabalin 150-mg capsule could be concluded. .