Novel Nanoemulsion Formulation for Ocular Drug Delivery for Cataract Therapeutics

This study aimed to create coated nanoemulsions for enhanced cataract therapeutics which would possess the smallest size, highest loading capacity, offer greatest physical stability for ocular drug delivery. Three different molecular weight (low, medium and high) chitosan were used for coating the cyclosporine A nanoemulsions. Better penetration, slow and sustained release of the drug from coated nanoemulsions in corneal region is the predicted advantage because of the mucoadhesive properties of the polymer. The coated nanoemulsions were formed by ultrasonication method with a previously established oil phase being oleic acid, surfactant being Tween 20 and co-surfactant being Transcutol P. Pseudo ternary phase illustrations were created to know the best surfactant: co-surfactant ratio which was determined to be 1:1. TEM studies exhibit coating on nanoemulsions and irregularities in coated nanoemulsions when compared to uncoated ones. Stability studies indicate almost no significant changes in size, Polydispersity index and Zeta potential of nanoemulsions after 60 days of being stored at room temperature. Cytotoxicity and in-vitro ocular inflammation studies indicate a non-irritant and non-toxic emulsion well tolerated by rabbit eye much more sensitive than human. The clinical scoring is between 0-0.3. Results of corneal penetration studies show % of drug penetration was 59.2 and 57.5%, 55.5% and 52.3% (low, medium high mol. weight chitosan coatings respectively). This is a promising alternative for cataract therapeutics since drug penetration in cornea was not significantly affected despite coating.