Hot-melt extrusion technique (HME) to develop intravitreal inserts

This study aimed to develop an ophthalmic insert containing fluocinolone acetonide (FA), to apply in the posterior segment of the eye. The inserts were prepared by the hot-melt extrusion technique (HME) and contained 3% FA and different polymeric materials chosen according to their suitability for extrusion and their potential use in ophthalmic field. The insert based on AMYLO-maize starch (AMYLO-FA) was selected on the basis of technological properties and in vitro drug release behavior. No substantial morphological changes following of AMYLO-FA in isotonic buffer solution hydration and swelling were observed up to 12 days. Drug release performance of AMYLO-FA, evaluated using Gummer-type diffusion cells to maintain the sink conditions, highlighted an anomalous non-Fickian release, and about 60% of FA content was delivered over 8 days. The release rate of FA was also determined when the receiving phase was totally replaced every 24h and 48h simulating the biological conditions of a stagnant vitreous humour. In any case, the obtained FA release was linear during the 25-day sampling period and release rates of 26.76 and 10.61 μg/day were obtained by replacing the receiving phase every 24 and 48 hours, respectively. Thus it seems that the FA release from the device was mainly influenced by the receiving environment rather than controlled from the insert.