Polydopamine-Coated Silicone Hydrogel Lenses for Enhanced Ocular Drug Delivery Using Curcumin-Loaded Chitosan Nanoparticles

Traditional methods of ocular drug delivery, such as eye drops, have limited effectiveness, with only ~5% of the administered dose reaching deeper ocular tissues due to rapid drainage and barriers like the corneal epithelium and blood-retinal barriers. Alternatives such as ocular implants, gels, microneedles, and iontophoresis can improve bioavailability but often cause discomfort, invasiveness, or require specialized equipment. This study explores using silicone hydrogel contact lenses for sustained drug delivery using polydopamine (PDA) coatings combined with curcumin-loaded chitosan nanoparticles. Optimized PDA coatings, achieved with a 250 ppm solution and 10-hour immersion, resulted in a uniform 1-3 µm thickness. Reaction time influenced nanoparticle distribution, with shorter times (1 hour) yielding narrower size distributions and reduced aggregation. At a chitosan-to-TPP ratio of 2:1, particles averaged 167.3 ±1.9nm, with a low PDI of 0.15-0.25, indicating uniformity. Ethanol minimized aggregation, resulting in narrower size distribution subsequently. Nanoparticles’ size increased with time, with sizes peaking ~100nm at 1 hour. Curcumin’s anti-inflammatory and antioxidant properties are protected from thermal degradation within chitosan nanoparticles, and PDA further stabilized the lenses. This approach offers a convenient, non-invasive alternative to traditional methods, potentially improving therapeutic outcomes and patient compliance in managing chronic ocular conditions.