Studies on the formulation and in vitro release of ophthalmic liposomes containing dexamethasone sodium phosphate

Several liposome formulations containing Dexamethasone Sodium Phosphate (DSP) were characterised in this study. For this purpose, phospholipids (gel and liquid types) and charge inducers, with or without cholesterol, were employed as bilayer components. Liquid state (PL 100:SA and PL 100:SA:CHOL) and gel state (PL 90H:SA and PL 90H:SA:CHOL) liposomes were prepared in molar ratios of (7:1:2), (10:1:4), (7:1) and (10:1). The film technique followed by sonication and membrane extrusion were used for the preparation of DSP liposomes. Particle size and particle-size distribution of MLVs, entrapment efficiency, free DSP (in supernatant) and, phospholipid content were determined for the characterization of the liposomes. The characterized liposomes were investigated for in-vitro release and different profiles were observed. The in-vitro release rates were evaluated kinetically and the best fitting equation was found to be the Higuchi equation.