Abstract: Aim The relative bioavailabilities of aniracetam capsules were studied. Methods The blood concentrations of the main metabolite of aniracetam, Nanisoyl- GABA (ABA), were determined by RPHPLC after a single oral dose of 400 mg aniracetam of test(capsules) or reference(capsules) drugs was given separately to 12 volunteers in an open randomized cross-over test. Statistical software’s 3p87 w ere used for the calculation of results. Results After taking a single oral dose of 400 mg aniracetam test capsules and reference capsules, thd AUC_0~t of aniracetam of the two formulations were (781.0 ±169.5) μg·min· ml^-1 and (792.3 ±156.6) μg·min·ml^-1; t_max were (40.9 ±9.7) min and (37.3 ±11.5) min; c_max of ABA were (10.4 ±3.0) μg ·ml -1 and (10.5 ± 3.0) μg ·ml^-1. The result s of statistical analysis showed that there were no significant difference in the AUC_0~t, t_max and c_max of ABA between the formulations (P <0.05). The relative bioavailability of aniracetam capsule was (99.4 ±14.4) %. Conclusion The two aniracetam capsules were bioequivalent.

Key words: aniracetam, N-anisoyl-GABA, pharmacokinetics, relative bioavaliability, HPLC