Oxidative stress is a pathophysiological condition defined by an increased production of reactive oxygen species (ROS), which can result in the growth arrest of cells followed by cell disintegration or necrosis. A number of small molecule antioxidants (e.g. curcumin, quercetin and resveratrol) are capable of directly scavenging ROS, thereby short-circuiting the self-propagating oxidative stress state. However, poor solubility and rapid 1st pass metabolism results in overall low bioavailability and acts as a barrier for its use as a drug to suppress oxidative stress efficiently.

To overcome this limitation, these small molecule antioxidants were covalently conjugated into poly(beta-amino ester) (PbetaAE) cross-linked networks to formulate prodrug gel microparticles and nanoparticles (nanogels). Being hydrolytically degradable in nature, these PbetaAE crosslinked systems released antioxidants in their original structural form in a sustained controlled fashion.

Both quercetin and curcumin-PbetaAE nanogels showed prolonged suppression of cellular oxidative stress induced by H2O2. Curcumin PbetaAE nanogels also demonstrated protection against mitochondrial oxidative stress induced by H2O2 and polychlorinated biphenyls. Curcumin-PbetaAE gel microparticles were also developed as a platform to treat oral mucositis through a local antioxidant delivery route. The same synthesis chemistry was transferred to formulate resveratrol PbetaAE gel microparticles for topical applications, to treat UV radiation induced oxidative stress. Both formulations showed suppression of induced oxidative stress. An in vivo trial with curcumin-PbetaAE microparticles further showed relatively reduced the severity of induced oral mucositis (OM) in hamster check pouch as compared to placebo.