Preparation of dexamethasone ophthalmic implants: a comparative study of in vitro release profiles.

Diseases affecting the posterior segment of the eye are the most common cause of visual disorders in industrialized countries. This scenario has encouraged the development of new treatment modalities for these diseases, such as drug loaded implants with prolonged drug release. The aim of the present work was to create a polymeric based biodegradable ophthalmic implant for the delivery of dexamethasone. For this purpose, we prepared and compared the in vitro release profiles of dexamethasone ophthalmic implants produced by two methods: melting casting and solvent casting. The type of the biodegradable polymer used - poly (ɛ-caprolactone) (PCL) and poly(lactic acid) (PLA); the drug loading (10% and 25%, w/w), the molecular weight of PCL (37 kDa and 14 kDa) and the form of the drug (dexamethasone and dexamethasone disodium phosphate) were also investigated. The results show that the preparation method has little influence on the obtained release profiles, being the type of polymer the most significant factor affecting the release profiles; nonetheless, a better distribution of dexamethasone was obtained for the devices prepared by melting casting.