Pharmacokinetics and bioequivalence evaluation of two gabapentin preparations after a single oral dose in healthy Korean volunteers.
OBJECTIVE
To evaluate the bioequivalence of a single oral 400 mg dose of 2 gabapentin preparations in healthy male Korean volunteers.


METHODS
The study was conducted as a randomized, 2-period crossover design in 26 healthy male Korean volunteers who received a single oral dose of 400 mg gabapentin capsule in each study period. There was a 7-day washout period between the doses. Serum concentrations of gabapentin up to 24 hours after the administration were determined using a validated HPLC method with fluorescence detection. In addition, in vitro dissolution profiles of both preparations were examined. The pharmacokinetic parameters such as AUC(0.t) (the area under the curve from zero to the time), AUC(0-infinity) (the area under the curve from zero to infinity), C(max) (maximum serum concentration), t(max) (time to reach C(max)) and t1/2 (terminal half-life) were analyzed by noncompartmental analysis, and the analysis of variance (ANOVA) was carried out using logarithmically transformed AUC(0-t), AUC(0-infinity) and C(max) and untransformed t(max).


RESULTS
In vitro dissolution profiles were very similar at all media. There were no significant differences between the two preparations in AUC(0-t), AUC(0-infinity) and C(max). The point estimates (90% confidence intervals) for AUC(0-t), AUC(0-infinity) and C(max) were 1.0319 (0.9142 - 1.1647), 1.0127 (0.8458 - 1.2127) and 0.9796 (0.8670 - 1.1069), respectively, satisfying the bioequivalence criteria of 0.80 - 1.25 as proposed by the US FDA and the Korean legislation. No statistically significant difference was found for tmax and t1/2 values.


CONCLUSIONS
From the results of the present study, it is indicated that the two preparations of gabapentin are bioequivalent and it can be assumed that they are therapeutically equivalent and exchangeable in clinical practice.
Cho
H Y
HY
College of Pharmacy and Institute of Bioequivalence and Hospital Bridging Study, CNUH, Chonnam National University, Gwangju, Korea.
Kang
H A
HA
Lee
Y B
YB
D000284:Administration, Oral; D000328:Adult; D000465:Algorithms; D000588:Amines / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000927:Anticonvulsants / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D019540:Area Under Curve; D044466:Asian People; D001682:Biological Availability; D002214:Capsules; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004339:Drug Compounding / Q000379:methods*; D000077206:Gabapentin; D006207:Half-Life; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D013810:Therapeutic Equivalency; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
D000588:Amines; D000927:Anticonvulsants; D002214:Capsules; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin