Development and Evaluation of a Sustained Release Microencapsules of Metformin Hydrochloride

A sustained release dosage form of Metformin HCl in the form of microspheres was prepared by the solvent evaporation method. Solvent evaporation method was attempted in both aqueous as well as oily manufacturing vehicles. Different polymers such as Ethyl Cellulose, Eudragit RS PO, Eudragit RL PO, Eudragit S 100, Eudragit RL 100 and different combinations of these polymers were tried and the resulting microspheres were evaluated for entrapment efficiency, drug loading and percent yield of the process and dissolution profile. The combination which showed the desired characters was chosen and further compared with a marketed formulation. The aim was to develop a multiparticulate sustained release drug delivery system to be converted to a liquid oral formulation, so that patient suffering from dysphagia, stroke, difficulty in swallowing, geriatric patients etc. may consume it easily and long term therapy may be maintained as required in patients suffering from osteoarthritis, diabetes.