Dexamethasone loaded blend poly hydroxybutyrate-stearic acid nanoparticles for ocular inflammation

The aim of this study is to develop and analyze dexamethasone-loaded poly hydroxybutyrate-stearic acid blend nanoparticles for the treatment of non-bacterial uveitis. Uveitis is a chronic inflammatory eye disease responsible for 10-15% of global blindness. While repeated intravitreal steroid injection is a successful treatment strategy, it has drawbacks such as cataracts and retinal detachment. Serious side effects and high costs caused by recurrent infections are important limiting factors. Controlled release systems are preferred to maintain therapeutic drug concentrations in the vitreous humor while minimizing the frequency of injections. In this study, PHB-stearic acid blend nanoparticles with varying ratios of dexamethasone suitable for intravitreal injection were fabricated. It was assessed the effects of the stearic acid ratio on loading efficiency, release profiles, size distribution, and thermal properties. The results indicated that an increase in the stearic acid ratio led to a reduction in nanoparticle diameter and an enhancement in the dexamethasone loading capacity. Additionally, higher stearic acid ratios resulted in a decrease in the melting enthalpy of the nanoparticles, which expedited dexamethasone release. Importantly, the nanoparticle formulations exhibited no toxicity to eye endothelial cells or THP-1 cells.