Biodegradable Additives Modulate Ganciclovir Release Rate From PLGA Microspheres Destined to Intraocular Administration

Human cytomegalovirus (HCMV) retinitis treated with frequent intraocular injections of ganciclovir is associated with complications such as endophthalmitis, retinal detachment and vitreous haemorrhage. Several formulations of biodegradable injectable PLGA microspheres with ganciclovir have been previously investigated as a possible alternative for treatment of HCMV retinitis. This report describes two new formulations of PLGA microspheres with ganciclovir that also include alpha tocopherol (vitamin E) or glyceryl tricaprylate/caprate (miglyol) as additives, modulating the release rate of ganciclovir. While additive free microspheres in vitro released about 90% of its ganciclovir within 20 days, the microspheres with the additives released only 20% of the drug during this period, and continued releasing the drug at the same rate for a total of 42 days.