Abstract: AIM: To compare the pharmacokinetics characteristics of dimenhydrinate orally disintegrating tablets (ODTs) and conventional tablets in rhesus plasma. METHODS: A randomized two-period, self-control crossover study with regard to the pharmacokinetic characteristics of dimenhydrinate ODTs and conventional tablets was executed in rhesus. The plasma concentrations of dimenhydrinate after oral administration of two formulations (both doses were 50 mg dimenhydrinate) were estimated by a simple, sensitive and specific HPLC-UV method. The pharmacokinetic parameters were computed by software DAS 2.0 and compared by statistic analysis. RESULTS: The relative bioavailability of dimenhydrinate ODTs (F_{0-12 h}, F_0-∞ were (154±42)% and (150±53)%, respectively, compared with conventional tablets. There was no significant difference in area under the plasma concentration (AUC_0-∞) (P>0.05) between the two formulations. Interestingly, there had statistically significant difference between the dimenhydrinate ODTs and conventional tablets in C_max, area under the plasma concentration (AUC_{0-12 h}) (P<0.05). Moreover, dimenhydrinate ODTs showed a markedly, but not significantly shorter t_max compared with conventional tablets (P>0.05). The method was sensitive with a lower limit of quantitation (LLOQ) of 10 ng/mL and good linearity in the range 10-2000 ng/mL for dimenhydrinate (r=0.99995). All the validation data, such as accuracy, precision, intra-day and inter-day repeatability, were within the required limits. CONCLUSION: Dimenhydrinate ODTs have a faster absorption compared with conventional tablets.

Key words: Dimenhydrinate, Orally disintegrating tablets, Pharmacokinetics