Comparative study on the bioequivalence of two different gabapentin formulations: A randomised, two-period, two-sequence, crossover clinical trial in healthy volunteers

The bioequivalence of two capsule formulations containing 400 mg gabapentin (CAS 60142-96-3) was assessed in 24 healthy volunteers in an open, randomised, crossover, 2 periods × 2 sequences, with a minimum washout period of 7 days, single-dose study. Plasma samples were obtained at fixed time points, over 48 h (baseline (pre-dose), +0.5 h, +1 h, +1.5, +2, +2.5, +3, +3.5, +4, +8, +5, +6, +8, +10, +12, +24, +36 and +48 h after administration) and gabapentin concentrations were determined by means of an HPLCMS method (LLOQ 50.2 ng/mL). Pharmacokinetic parameters used for bioequivalence assessment (AUC tlast, AUCinf and Cmax) were determined from the gabapentin concentration data using non-compartmental analysis. The results showed that all 90% confidence intervals (obtained by ANOVA) were all within the predefined ranges: 93.87-111.87% for Cmax, 94.04-108.21% for AUCtlast, and 94.23-108.29% for AUCinf. Consequently, this bioequivalence study was well designed in order to conclude that the test formulation and reference formulation were bioequivalent in terms of rate and extent of absorption. © ECV · Cantor Verlag, Aulendorf (Germany).