Ocular Delivery of Atenolol Loaded Microsponge in-situ Gel: Development, Characterization and in-vitro Evaluation

Aim/Background: The purpose of the study was to fabricate and evaluate atenolol loaded micro-sponge in-situ gel. Materials and Methods: Oil in Oil Emulsion Solvent Diffusion Technique was used for formulation of microsponges by using different levels of polymers such as Eudragit RS-100 and Ethyl Cellulose. The prepared micro-sponges were evaluated for optical microscopy, percentage yield, drug content, entrapment efficiency and surface morphology studies. The micro sponges were loaded into in-situ gel. The gel was characterized for pH, rheological behavior, in vitro gelling capacity and in vitro drug release study. Results: The smicrosponges were found in the size range of 7.43 to 9.26 mu m. The formulation F1 has smallest particle size while F9 has largest size. The product yield varies from 66.98% to 89.87 %.The drug content was found to be maximum for formulation F8 which is 94.19%. Similarly, the entrapment efficiency was found maximum for formulation F8 which is 93.89%. The gel was characterized for pH. The pH of drug loaded microsponge gel were found in range of 7.43 +/- 0.27 to 9.26 +/- 0.61.Similarly, viscosity ranges from 32 to 39 cps. The data of in-vitro release shows that 60.12% drug was released up to 24hr. Conclusion: The mirosponges laden in situ gel was effectively prepared by oil in oil emulsion solvent diffusion method (O/O ESDM). Further, the formulation will provide benefits in terms of sustained/controlled release, reduces dosing frequency and provides better compliance to the patient.