MULTIPLE DOSE PHARMACOKINETIC AND BIOAVAILABILITY OF ORAL ADMINISTRATION SUSTAINED RELEASE AND CONVENTIONAL TABLETS OF TRAMADOL HYDROCHLORIDE

The pharmacokinetics and bioavailability of a new sustained release tablet (100 mg q 12 h5 d) of tramadol hydrochloride was investigated with a conventional tablet (50 mg q 6 h5 d) after multiple oral administration in ten healthy volunteers using an open, randomized, two-way crossover design.The tramadol hydrochloride concentration in plasma was determined by RP-HPLC method with fluorescence detecter. The results showed that the Tmax of sustained release tablet was 4.330.39 h, later than that of conventional tablet (1.720.32 h). The AUC0-12 of sustained release tablet and conventional tablet were 3767.63570.37 ghL-1 and 3838.79914.31 ghL-1 respectively (P0.05). The relative bioavailability of sustained release tablet to conventional tablet wes 97.9%.The Cmax,Cmin of sustained release and conventional tablets were 451.0640.98 gL-1 and 483.7383.17 gL-1 (P0.05); 219.0644.53 gL-1 and 175.2886.26 gL-1 (P0.05)respectively. The FI of sustained release tablet was less than that of conventional tabl