Formulation development and oral permeability of metformin HCl under the influence of permeability enhancers

Oral drug development is the largest and oldest segment of total drug delivery in the market. It is the fastest-growing and most preferred route of administration. The major challenge in oral drug delivery is the development of novel dosage forms to promote the absorption of poorly permeable drugs across the intestinal epithelium. Metformin HCl is an orally administered biguanide that is widely used in the management of type II diabetes throughout the world. It is a BCS class III drug; it cannot be absorbed orally owing to its very low permeation through the GIT epithelium. The object of the present investigation was to evaluate an oral drug approach that involves co-administration of absorption enhancers. The result indicates that there is a significant impact of permeation enhancers on the improvement in the permeability of the drug. Permeation enhancers and drugs were formulated in tablet form and further evaluated for permeability by using biological membranes. Release of the drug from the tablet in both acidic and alkaline media was found to be higher in the alkaline medium than in the acidic medium. Hence, the addition of absorption enhancers in a formulation at low concentrations can significantly improve the intestinal permeability of Metformin HCl without any side effects like lactic acidosis or gastric irritation and improve bioavailability.