Anthony Soluri, HBSc is an optometry student at the University of Waterloo School of Optometry and Vision Science and researching drug delivery via contact lenses at the Centre for Contact Lens Research.
Download the poster (.pdf), which was originally shared at the Association for Research in Vision & Ophthalmology (ARVO) annual meeting, 2012.
Ocular delivery of ketotifen fumarate by silicone hydrogel and conventional hydrogel contact lens materials
Anthony Soluri, HBSc, Alex Hui, OD, and Lyndon Jones, PhD
Centre for Contact Lens Research, School of Optometry, University of Waterloo
Objectives: To investigate the uptake and delivery of the anti-allergy drug ketotifen fumarate (KF), by commercially available contact lenses.
Methods: A total of fourteen different commercially available contact lenses were investigated, including five frequent replacement silicone hydrogels (balafilcon A, comfilcon A, galyfilcon A, senofilcon A and lotrafilcon B), three conventional hydrogels (alphafilcon A, etafilcon A, and polymacon) and six daily disposable lenses (nelfilcon A, omafilcon A, etafilcon A + PVP, ocufilcon B, narafilcon A and filcon II 3). Lenses were soaked in a 0.025% KF loading solution for 24 hours, and the concentration of KF in solution over time was determined by UV absorbance at 297 nm. After the 24 hour loading period, lenses were placed into fresh vials containing borate buffered saline (BBS), and the release of drug into solution at 34°C was monitored over 24 hours.
Results: All the lenses studied demonstrated significant uptake and release of KF into the BBS (p<0.05 compared to initial time point). Lenses with charged surfaces (balafilcon A, etafilcon A and etafilcon A + PVP) demonstrated the greatest uptake and release of KF. Etafilcon A released 284.5 ± 29.8 µg/lens, while balafilcon A released 227.6 ± 14.7 µg/lens, which was substantially more (p<0.05) than the lowest releasing lenses (nelfilcon A; 40.4 ± 4.1 µg/lens and comfilcon A; 110.4 ± 8.9 µg/lens). The majority of lenses were able to match or exceed the total amount of KF commonly administered to the eye using twice daily dosing of commercially available (0.025%) eye drop formulations. Most of the lenses surveyed released to a plateau concentration of KF relatively quickly, and no lens was able to release KF for longer than four hours.
Conclusions: Commercially available lenses demonstrated the ability to release a clinically relevant amount of KF compared to conventional eye drops. The use of commercially available contact lenses as a KF delivery system in a daily disposable wear scenario may be feasible.
Acknowledgements: Alex Hui is supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Canadian Optometric Education Trust Fund (COETF), and a Vistakon® Research Grant and Ezell Fellowship, both administered by the American Optometric Foundation (AOF). This study is also supported by the NSERC 20/20 Network for the Development of Advanced Ophthalmic Materials.