Investigation on the pharmacokinetics of the two kinds of metformin hydrochloride sustained-release pellets in healthy volunteers

Objective To investigate the pharmacokinetics and relative bioavailability of the pH-dependent (T1) and non-pH-dependent (T2) sustained-release metformin hydrochloride pellets.Methods A single oral dose of 1 000 mg of conventional metformin hydrochloride,T1 and T2 was given to 18 healthy volunteers in a random crossover design.The drug concentration in the plasma was determined by the HPLC method.The pharmacokinetic parameters and the relative bioavailability were measured.Results The pharmacokinetic parameters of the metformin hydrochloride in conventional tablets,T1 and T2 were ρ max (2.38±0.41),( 1.62±0.34) and (0.92±0.28)mg·L -1;t max (2.72±0.46),(5.56±0.86) and (4.33±0.82) h;AUC 0→24(14.50±2.83),(14.91±2.52) and (6.63±1.96) mg·h·L -1; t MRT (5.21±0.54),(8.26±0.51) and (6.89±0.40) h,respectively.Compared with commercial tablets,the relative bioavailability of T1 and T2 was103.6% and 45.7%,respectively.Conclusions An obvious characteristic of the sustained-release pellats is shown in the concentration-time curves of metformin hydrochloride in T1 in healthy volunteers.T1 and commercial tablets are bioequivalent.