Pharmacokinetic equivalence study of two formulations of the anticonvulsant pregabalin.

Purpose: The present study was conducted to evaluate whether the bioavailability of pregabalin capsules 150 mg manufactured by PT Dexa Medica was equivalent to the reference formulation.

Methods: This was a randomized, open-label, two-period, two-sequence, and crossover study under fasting condition, with a 1-week washout period. Plasma concentrations of pregabalin from 20 subjects were determined by using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) detection method. Pharmacokinetic parameters assessed in this study were: area under the plasma concentration-time curve from time zero to last observed quantifiable concentration (AUC0-t), area under the plasma concentration-time curve from time zero to infinity (AUC0-∞), maximum plasma concentration (Cmax), time to maximum plasma concentration (tmax), and terminal half-life (t1/2). The 90% confidence intervals (CIs) for the geometric mean ratios of test formulation/reference formulation were calculated for the AUC and Cmax parameters; while tmax difference was analyzed nonparametrically on the original data using the Wilcoxon matched-pairs test, and t1/2 difference was analyzed using Student's paired t-test.

Results: The mean (standard deviation [SD]) AUC0-t, AUC0-∞, Cmax, and t1/2 of pregabalin from the test formulation were 27,845.86 (4,508.27) ng · h/mL, 28,311.70 (4,790.55) ng · h/mL, 3,999.71 (801.52) ng/mL, and 5.66 (1.20) hours, respectively; while the mean (SD) AUC0-t, AUC0-∞,Cmax, and t1/2 of pregabalin from the reference formulation were 27,398.12 (4,266.28) ng · h/mL, 27,904.24 (4,507.31) ng · h/mL, 3,849.50 (814.50) ng/mL, and 5.87 (1.25) hours, respectively. The median (range) tmax of pregabalin from the test formulation and reference formulation was 1.00 (0.67-2.00) hours and 1.00 (0.67-3.00) hours, respectively. The 90% CIs for the geometric mean ratios of test formulation/reference formulation for pregabalin were 101.54% (98.75%-104.41%) for AUC0-t, 101.35% (98.66%-104.11%) for AUC0-∞, and 104.19% (98.75%-109.93%) for Cmax.

Conclusion: The study concluded that the two formulations of pregabalin capsules studied were bioequivalent.