Biodegradable ocular implant for sustained drug delivery
Date of Issue2011
School of Materials Science and Engineering
Singapore Eye Research Institute, Singapore National Eye Center
This thesis is aimed to develop a drug loaded microfilm, which can release drug at in a controlled manner sustainably, with comparable or better therapeutic effect to that seen with drug loaded the eye drops. This thesis presents the development progress of the drug releasing microfilm, which includes the investigation of the degradation behaviour of the candidate biomatrix materials and the drug release performance from the matrix biomaterial as effects of diffusion and degradation. Microfilms, which was were made of two candidate materials, (poly [d,l-lactide-co-glycolide] with lactide/glycolide ratio of 53/47 (mol %/mol %) PLGA5347 and poly[d,l lactide-co-caprolactone] with lactide/caprolactone ratio of 70/30 (mol %/mol %) PLC7030) were developed and evaluated for their degradation behaviour in vitro and in vivo. PLGA5347 and PLC7030 both exhibited bulk degradation mechanism in vitro, with exponentially decaying molecular weight (Mw) and unchanged film thicknesses. In vivo, PLGA5347 degraded homogeneously and became non-visible in the rabbit eyes three3 months after the study; whereas PLC7030 persisted throughout 6 months, with unchanged width and length, but linearly decreasing film thickness. This is the first time reporting that biodegradable polymers hydrolyze homogeneously in vitro but heterogeneously in vivo.