Engineering and development of chitosan-based nanocoatings for ocular contact lenses

This manuscript reports on Electrohydrodynamic Atomisation (EHDA) to engineer on-demand novel coatings for ocular contact lenses. A formulation approach was adopted to modulate the release of timolol maleate (TM) using chitosan and borneol. Polymers polyvinylpyrrolidone (PVP) and poly (N-isopropylacrylamide) (PNIPAM) were utilised to encapsulate TM and were electrically atomised to produce optimised, stationary contact lens coatings. The particle and fibre diameter, thermal stability, material compatibility of the formed coatings; their in vitro release-modulating effect and ocular tolerability were investigated. Results demonstrated highly stable nano-matrices with advantageous morphology and size. All formulations yielded coatings with high TM encapsulation (>88%); excellent ocular biocompatibility. Coatings yielded biphasic and triphasic release; depending on composition. Kinetic modelling revealed a noticeable effect of chitosan; the higher the concentration, the more the release of TM due to chitosan swelling; with the mechanism changing from Fickian diffusion (1% w/v; n = 0.5) to non-Fickian (5% w/v, 0.45 < n < 0.89). The use of EHDA has not yet been explored in depth within the ocular research remit; engineering on demand lens coatings capable of sustaining TM release. This is likely to offer an alternative dosage form for management of glaucoma with particular emphasis on improving poor patient compliance.