Single dose metformin kinetics after co-administration of nisha-amalaki powder or mamejwa ghanavati, ayurvedic anti-diabetic formulations: A randomized crossover study in healthy volunteers

Objective: The aim was to study herb-drug interaction of two ayurvedic formulations - DMFN01 (Nisha-Amalaki) powder and DMFN02 (Mamejava) ghanavati with metformin at a single dose in healthy volunteers. Materials and Methods: This was an open-labelled, single dose, crossover, and randomized volunteer study. Healthy volunteers were studied in two groups (6/group). Volunteers were randomized to oral metformin (500 mg single dose) alone or with concurrent DMFN01 (10 g), or DMFN02 (750 mg). Venous blood samples were collected at different time points from 0 to 24 h. Plasma metformin concentrations were measured by high performance liquid chromatography coupled with an ultraviolet detector. Results: Simultaneous administration of DMFN01 with metformin showed a reduction in the mean area under the curve (AUC [0-24 h]) of metformin by 51% (P < 0.002) when compared with metformin alone. However, co-administration of DMFN02 did not show any significant difference in the mean AUC of metformin (P = 0.645). One volunteer had a reduction of 41% in AUC of metformin with DMFN 02. Conclusions: These data raise relevant questions on therapeutic control of hyperglycemia when DMFN01 choorna is given concurrently with metformin. Based on known absorption pattern of metformin an interval of 2 h between the oral doses of metformin and ayurvedic formulations would be advisable to avoid interactions. In reverse pharmacological studies, at an early stage, such interaction studies are desirable.