Nanostructured TPGS Micelle-Eluting MiSight® contact lenses for stabilized and sustained atropine delivery

Myopia, a leading cause of vision impairment among children worldwide, is commonly managed with low-dose atropine eye drops (0.01% w/v) or contact lenses that induce peripheral myopic defocus. This study aimed to enhance clinical outcomes by combining atropine with MiSight® daily disposable contact lenses while overcoming the instability of atropine under wet conditions at physiological pH 7.4. To address this challenge, atropine was encapsulated in tocopherol polyethylene glycol 1000 succinate (TPGS) micelles, allowing improved retention of atropine assay content under physiological pH 7.4 storage conditions and sustained release. The atropine-loaded micelles-laden lenses exhibited favorable wettability (70.39° ± 2.84 at the highest loading), equilibrium water content, and optical transmittance. Langmuir-Blodgett studies confirmed that micelles improved surface pressure and promoted stable surfactant rearrangement, supporting tear film stability. In vitro release studies demonstrated sustained atropine release over 8 hours. Cytotoxicity studies using human corneal epithelial cell lines confirmed the safety of the lenses. In vivo rabbit studies revealed prolonged atropine release into tear fluid, achieving a higher area under the curve (AUC = 11.47 ± 3.5 µg*h/mL) and mean residence time (MRT = 3.24 h) compared to conventional eye drops (AUC = 4.23 ± 2.1 µg*h/mL; MRT = 0.39 h). Furthermore, a significant pupil size increment (1.26 ± 0.68 mm over 12 h) was observed with atropine-loaded micelles-laden lenses compared to 0.69 ± 0.54 mm with eye drops. These findings suggest that micelle-based contact lenses offer a promising therapeutic platform for sustained ocular delivery of atropine, supporting prolonged tear exposure compared with eye drops; longer-term studies are required to confirm myopia-control endpoints (SER/axial length) and tolerability outcomes (e.g., photophobia/light sensitivity), which were not directly assessed in this study.