Formulation and Evaluation of Glibenclamide Osmotic Controlled Drug Delivery Systems

The objective of the study was to develop Controlled porosity and elementary osmotic pump-based drug delivery systems of Glibenclamide. The elementary osmotic pump (EOP) consists of an osmotic core with the drug surrounded by a semipermeable membrane drilled with a delivery orifice through which drug releases where as in controlled porosity osmotic pump drug release is accomplished by the use of pore forming agents in the coating. The usual dose of Glibenclamide is 5 mg to be taken three or four times daily. It has a short plasma half life of 2-6 hrs. Hence, Glibenclamide was chosen as a model drug with an aim to develop a controlled release system for a period of 12 hrs. Sodium chloride and mannitol were used as the osmogents. Osmotic tablets of Glibenclamide were prepared using wet granulation method and coated with semipermeable layer of ethylcellulose. The tablets were evaluated for their flow properties, hardness, weight variation, friability, drug content and all the results were found to be within the limits. In vitro release study was performed in 0.1NHCl for 2hrs and in pH 7.4 buffer for 10hrs.The effect of different concentrations of osmotic agents on the in-vitro release was studied.It was found that drug release rate increased with the amount of osmotic agent due to the increased water uptake, and hence increased driving force for drug release. Sodium chloride containing formulations showed highest drug release compared to mannitol due to high osmotic pressure.The release profile of formulation was fitted to different kinetic models and it was found to follow zero order kinetics.The optimized formulation was characterized by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM).