Chitosan-N-acetylcysteine modified HP-β-CD inclusion complex as a potential ocular delivery system for anti-cataract drug: Quercetin

The aim of this study was to develop a novel ocular drug delivery system based on the hydroxypropyl beta cyclodextrin (HP-β-CD) inclusion complex coated with the synthesized chitosan-N-acetyl- l -cysteine conjugate (CS-NAC) for the hydrophobic drug quercetin . The inclusion complex was prepared by the solvent evaporation method, and the concentration of HP-β-CD and CS-NAC was optimized by isolated corneal penetration test. The optimized concentration of HP-β-CD and CS-NAC was 20% (w/v) and 0.1% (w/v), respectively. The CS-NAC/quercetin-HP-β-CD had the effect on improving the ocular penetration with little ocular irritation and could increase the ocular distribution significantly. Meanwhile, Coumarin-6 (C6) labelled CS-NAC/C6-HP-β-CD possessed enhanced fluorescence and located deeper into the epithelium of cornea at the same time point compared with the uncoated one. It could also transport drug through the corneal epithelium by intracellular routes except for intercellular routes. Furthermore, it could delay the occurrence of cataract about 1 d when administrated with full-dosage quercetin. The HP-β-CD inclusion complex coated with CS-NAC is a safe and promising ocular drug delivery system for improving the bioavailability and corneal penetration of hydrophobic drug like quercetin.