Contact lenses with dual drug delivery for the treatment of bacterial conjunctivitis.

Currently, bacterial conjunctivitis is treated by frequent administration of antibiotic eye drop solutions, which is tedious and patient noncompliant. Contact lenses could be ideal medical devices to sustain the release of ophthalmic drugs, but the incorporation of the latter can alter the optical and physical properties of the lenses. In addition, many contact lens users have reported the pink eye syndrome, making them unsuitable as ocular medical devices. In the present study, we have designed a novel type of lenses containing semi-circular rings loaded with moxifloxacin HCl (a broad spectrum antibiotic) and hyaluronic acid (a comfort agent), respectively, in order to treat bacterial conjunctivitis without altering the critical lens properties. The drug loaded rings were implanted separately within the periphery of the contact lenses using the modified cast moulding technology. The atomic force microscopy report showed an average roughness of 22.27 nm for the implant lens, which was significantly lower in comparison to the marketed Freshlook® (116.27 nm) contact lens. The major amount of moxifloxacin HCl was leached (68.16-74.55%) during the monomer extraction and wet sterilization (autoclave) steps; hence the lenses were terminally sterilized by radiation and packaged under dry condition (dehydrated). The in vitro release data showed release for moxifloxacin HCl and hyaluronic acid up to 96 h. The in vivo drug release studies showed significant improvement [>MIC for Staphylococcus aureus] in the drug residence time in comparison to the eye drop therapy. The in vivo efficacy study in the staphylococcus aureus induced conjunctivitis showed equivalent healing effect with the single implant contact lens in comparison to the frequent high dose eye drop therapy. The study demonstrated the successful application of the implantation technology to co-deliver moxifloxacin HCl and hyaluronic acid from the contact lenses for the extended period of time to treat conjunctivitis.

Design and optimization of a novel implantation technology in contact lenses for the treatment of dry eye syndrome: In vitro and in vivo evaluation.

Contact lenses are widely used for ophthalmic drug delivery, but incorporation of drug or formulation in the contact lenses affects its optical and physical property. In the present study, we have designed a novel hyaluronic acid (HA)-laden ring implant contact lenses (modified cast moulding method), to circumvent the changes in critical lens property. The objective was to improve the ocular residence time of HA, by providing sustained ocular HA delivery through implant contact lenses for the treatment of dry eye syndrome. Optimization of HA-implant was carried out using 32 factorial design by tailoring the amount of cross linker and thickness of implant, to achieve sustained HA release with constraint on effective ion diffusivity. The in vivo pharmacokinetic study in rabbit tear fluid showed sustained HA release up to 15days, by fabricating implant (80µgHA loading) with 78.4µm thickness (total thickness of lens=100µm) using 0.925% of cross linker, with effective ion diffusivity>1.5×10-6mm2/min. In vivo efficacy study in benzalkonium chloride induced dry eye syndrome rabbits showed faster healing with implant contact lenses in comparison to positive control group. The study demonstrated the promising potential of implantation technology to deliver hyaluronic acid without compromising optical and physical properties of contact lens. STATEMENT OF SIGNIFICANCE: The limitation of contact lenses to be used as therapeutic device for controlled drug delivery is focused in this study. Incorporation of drug or formulation in the biomaterial affects the optical and physical property of contact lenses. The significance of project was to design a novel hyaluronic acid-laden ring implant contact lenses, to by-pass the changes in critical property of biomaterial.