Dexamethasone PLGA Microspheres for Sub-Tenon Administration: Influence of Sterilization and Tolerance Studies

Many diseases affecting the posterior segment of eye require repeated intravitreal injections with corticosteroids in chronic treatments. The periocular administration is a less invasive route attracting considerable attention for long-term therapies. In present work, dexamethasone-loaded poly(lactic-co-glycolic) acid (PLGA) microspheres (Dx-MS) were prepared using oil-in-water (O/W) emulsion solvent evaporation technique. MS characterized terms mean particle size and distribution, external morphology, polymer integrity, drug content, vitro release profiles. sterilized by gamma irradiation (25 kGy), dexamethasone profiles from non-sterilized compared means similarity factor (f2). mechanism before after exposure Dx-MS was identified appropriate mathematical models. Dexamethasone sustained 9 weeks. evaluation vivo tolerance carried out rabbit eyes, which received sub-Tenon injection 5 mg (20–53 µm containing 165.6 ± 3.6 µg Dx/mg MS) equivalent to 828 Dx. No detectable increase intraocular pressure reported, clinical histological analysis ocular tissues showed no adverse events up 6 weeks administration. According data presented this could be promising alternative successive treatment back eye.