The purpose of the current investigation was to explore the influence of a poly herbal formulation (PHF) on pharmacokinetics and pharmacodynamics of metformin in rats. The current investigation was undertaken to investigate the favorable results of PHF coupled with metformin by examining herb-drug interactions. PHF was made by five indigenous herbs, that are being utilized historically as antidiabetic in India. PHF dosages (100 mg/kg/day) were supplied to Sprague-Dawley rats via an oral route of distinct groups for multiple weeks except for control. Metformin (100 mg/kg) was orally delivered at 7th and 30th day to control and PHF pretreated rats for pharmacokinetics investigation while pharmacodynamics study was done in PHF treated and untreated diabetic rats. No further significant change was identified in the pharmacokinetic parameters in PHF treatment at 7th day whereas a substantial rise was reported in AUC at the 30th day.

The hypoglycemic effect was detected with a combination of metformin and PHF, considerably greater compared to control. Metformin lowered the blood glucose 1.51 fold at 7th day and 1.7 fold at 30th day correspondingly, compared to control. Thus, this data implies that PHF enhanced the AUC of metformin. It could in- crease bioavailability via drug-herb interaction hence changing the therapeutic impact. This formulation may be regarded as an addition to metformin in the therapy of diabetic mellitus.