In Vitro and In Vivo Studies of Polyvinyl Pyrrolidone-Coated Sparfloxacin-Loaded Ring Contact Lens to Treat Conjunctivitis.

Currently, conjunctivitis is treated by frequent high dose administration of sparfloxacin eye drop solution. However, the eye drops are inconvenient because of low bioavailability, short ocular drug residence time, and need of frequent instillation, which lead to patient noncompliance affecting the routine life style of patients. Silicone contact lenses can be used to sustain the release of sparfloxacin. However, the presence of sparfloxacin alters the optical and physical properties of the contact lens. To overcome the issues, a novel polyvinyl pyrrolidone (PVP)-coated sparfloxacin-laden ring contact lens was designed to provide sustained ocular drug delivery without altering the optical and swelling properties of contact lens. The ring was implanted within the periphery of the lens. Sparfloxacin was loaded by soaking (Sp-S), direct loading (Sp-L), and ring casting method (Sp-R). PVP (comfort agent) was coated on the surface of contact lens by novel short surface curing technique. The in vitro sparfloxacin release data of Sp-S (up to 12-36 h) and Sp-L batches (up to 12-24 h) showed high burst release, whereas Sp-R batch showed sustained release up to 36-48 h without significant (p > 0.05) alteration of the optical and swelling properties. All the batches showed sustained release of PVP up to 48 h. The in vivo release studies in the rabbit tear fluid showed improvement in the sparfloxacin [>MIC for Staphylococcus aureus] and PVP retention time in comparison to eye drop solution. The in vivo efficacy study in the S aureus-induced conjunctivitis showed improved healing effect with the single PVP-coated Sp-R-300 contact lens in comparison to the frequent high-dose sparfloxacin eye drop therapy. The study demonstrated the successful application to codeliver sparfloxacin and PVP from the contact lens for the extended period to treat conjunctivitis.