Development of Contact Lenses Loaded Thiolated Nanoparticles for Ocular Delivery of Tobramycin

C ommon ocular bacterial infections are treated mainly by antibiotic formulations in the form of eye drops or eye ointments. Conventional therapy requires frequent re-administration due to decreased pre-corneal retention because of lacrimal drainage, conjunctival absorption, and tear dilution. The present study is aimed at developing thiolated nanoparticles of tobramycin loaded onto contact lenses for extended topical delivery of tobramycin to improve its therapeutic efficacy, precorneal retention, and corneal permeability. Thiolated chitosan nanoparticles were prepared and optimized and then tobramycin was loaded onto them. The optimized drug-loaded nanoparticles had a particle size of 82.19 nm with a PDI of 0.210, zeta potential of 8.26 mV, and 76.39% entrapment efficiency. The optimized drug-loaded nanoparticles were then loaded onto contact lenses. The results indicated that nanoparticle-loaded contact lenses were able to release tobramycin for around 21 h as compared to the marketed eye drops which released 89% of the drug in 8 h. They were also found to be well-tolerated by the eye, suggesting that they could potentially serve as an excellent alternative to conventional eye drops for treating prevalent bacterial infections.