Aim: This study characterized ex vivo release of ketotifen from etafilcon A contact lenses worn over 5 h. Materials & methods: 14 participants, 21 to 59 years, wore lenses with 19 μg ketotifen over 8 visits, for 1 min to 5 h. Residual ketotifen was measured using high-performance liquid chromatography (HPLC) compared with unworn lenses from the same lots to determine percent ketotifen remaining. Results: Residual ketotifen ranged from 16.19 μg ± 0.44 (84.1%) [1 minute] to 0.20 μg ± 0.07 (1.1%) [5 h]. No adverse events or clinically significant biomicroscopy changes were observed. Conclusion: The ketotifen-releasing etafilcon A lenses were well-tolerated with an acceptable safety profile in the population studied. The release of ketotifen from study lenses over 5 h was consistent with a diffusion-controlled system.
Keywords: antihistamine; contact lens; drug eluting; drug release; hydrogel; ketotifen; ocular allergy; ocular itch.
This article is about measuring how fast a medication to relieve itchy eyes from allergies is released from contact lenses that are worn for a single day and then discarded. The study showed that the medication is initially released rapidly over the first 15 min of wear and then more slowly over the next 4+ h until almost none remains. This means that people who have itchy eyes from allergies may be able receive their medication by just wearing these contact lenses each day during their allergy season, without having to put in extra eye drops.