摘要：

Objectives:To investigate the pharmacokinetics and relative bioavailability of metformin hydrochloride sustained-release tablets(ST).Methods:A sensitive and rapid HPLC method was developed to determine the metformin plasma concentration.ST and regular tablets(RT) of single and repeated dose were orally administrated to healthy volunteers in randomized crossover design.The plasma samples were analysed on a Diamonsil C_(18) column after precipitation of protein with acetonitrile.The mobile phase was a mixture of methanol,10 mmol·L~(-1) sodium dodecyl sulphate,0.02 mmol·L~(-1) potassium dihydrogen phosphate(pH 3.7),at a flow rate of 1.0 mL·min~(-1).The UV detector was set at 233nm.Results:The C_(max)(2126 ng·mL~(-1))of RT after single oral dose in 20 healthy volunteers was significantly higher than that(1660 ng·mL~(-1)) of ST.The T_(max) (4.2h) of ST was significantly longer than that(2.5h)of RT(P 0.05).The relative bioavailability of ST was found to be 97.0%.The C_(min) of ST and RT at steady state were 104ng·mL~(-1) and 296ng·mL~(-1),and the C_(max) of ST and RT were 1674 ng·mL~(-1) and 1692 ng·mL~(-1),respectively.Conclusion:ST of metformin hydrochloride was bioequivalent to its RT.ST exhibited a sustained-release property with a significantly longer T_(max) and a lower C_(max).

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