An oral monolithic osmotically controlled delivery system for Cefixime using controlled porosity membrane technology was developed and evaluated . Unlike conventional osmotic systems, which require laser drilling, this system releases the drug in a controlled manner from asymmetric membrane coated core tablets . Asymmetric membrane is formed by solvent evaporation process with co solvency technology process using cellulose acetate as the coating material . Higher water influx of this membrane aids in delivery of Cefixime, which is highly water insoluble . The porous structure of the membrane was confirmed by scanning electron microscopy . Influence of different osmotic agents (Nacl & Mannitol) on drug release was evaluated . In vitro release studies showed that as concentration of osmotic agents was increased, the drug release was also enhanced . Drug release from the developed monolithic system was independent of external agitation and pH of dissolution media . Comparative in vitro release data was obtained using different levels and concentrations of coating membranes in controlled porosity membrane, different level of osmogent and with water soluble cellulose acetate phthalate in controlled porosity coating membrane . The optimized formulation follows zero order release mechanism. The FTIR and DSC studies revealed that no physicochemical interaction between excipient and drug . The influence of pH and agitation intensity on the release of drug was studied and the release mechanism was through osmosis . Stability studies revealed that optimized formulation was stable. The osmotic pressure developed was found to be linearly proportional to time and concentration of osmotic agent. The solubility and availability of water insoluble drug (Cefixime) was enhanced by use of solublizing agent SLS (3 .63 %) .
