Pharmacokinetics and bioavailability of dextromethorphan chewable tablets

AIM The pharmacokinetic profiles and the bioavailability of dextromethorphan chewable tablets were studied in 10 normal male volunteers METHODS Dextromethorphan was administered in a single dose of 60 mg in random order The plasma concentration of dextromethorphan and its main metabolite,dextrorphan,were determined by HPLC fluorescene method RESULTS The characteristics of the plasma concentration time curve fitted to one compartment model The pharmacokinetic parameters for dextromethorphan tablets and chewable tablets were as follows respectively:DM: T 1/2 :(2 75±0 87) h ,(2 92±1 03) h; T max :(1 81±0 59) h,(1 75±0 65) h; C max :(31 09±11 01),(33 09±13 48) μg·L -1 ;AUC:(169 12±82 94),(166 95±78 23) μg·h -1 ·L -1 ;the relative bioavailability was (104 02±10 37)%. DP: T 1/2 :(3 09±1 06) h, (2 95±1 08) h; T max :(2 30±0 48) h ,(1 9±0 7) h; C max :(838 55±323 78),(828 37±319 4) μg·L -1 ;AUC:(4177 43±1077 79),(4143 11±1273 76) μg·h -1 ·L -1 . CONCLUSION The relative bioavailability was 99 26%±16 31%. The results of analysis of variance,two one sided tests and (1-2α)90% showed that two formulations were bioequivalent.