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Brian L Pall, Shivkumar Mahadevan, Azaam Alli, Frank Yi, Charis Lau, Paul J Gomes; The ex vivo drug amount and clinical efficacy of an antihistamine releasing contact lens over time. Invest. Ophthalmol. Vis. Sci. 2020;61(7):1498.
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A ketotifen-releasing contact lens is a novel approach to prevent itching associated with ocular allergy for subjects who require refractive correction. The drug release profile of this antihistamine releasing contact lens was measured and evaluated against previously established efficacy results.
A single center, open-label, clinical trial was conducted to assess the amount of ketotifen remaining in the lens after wear using high performance liquid chromatography (HPLC) analysis. Adult subjects with a history of normal ocular health and habitual contact lens wear were enrolled. Subjects wore ketotifen releasing lenses bilaterally for specified time periods (1, 5, 15, 30, and 45 minutes and 1, 2, and 5 hours of wear) over 8 different visits and lenses were collected after each visit to measure the residual ketotifen in each lens via HPLC. The percentage of residual ketotifen was then calculated (ketotifen in lens following wear/average amount of ketotifen of the relevant lens lot prior to wear) for all subjects at all time points. Additionally, the remaining ketotifen was compared between the right eye and left eye for each wear period with a paired t-test. The onset, and duration of action of the ketotifen releasing lenses were previously investigated in two multicenter, randomized, placebo-controlled studies.
14 subjects (28 eyes) were enrolled and dispensed study lenses with 11 subjects (22 eyes) completing all 8 study visits. The mean (SD) percentage of residual ketotifen in lenses was 53.2% (3.2%) after 15 minutes, 23.3% (4.0%) after 1 hour, 9.1% (3.2%) after 2 hours, and 1.0% (0.4%) after 5 hours. There were no statistically significant differences in the mean percentage of residual ketotifen at any time point between the right and left eyes (p=0.144 or greater for all time points). Previously published results demonstrate a clinically and statistically significant reduction in ocular itching with the ketotifen releasing contact lens after 15 minutes and 12 hours of wear.
The ketotifen containing study lenses exhibit a consistent release of the antihistamine during the wear-period. Approximately 80% of the drug present in the lenses is released every hour based on what is remaining in the lens over a 5-hour period. This release profile is consistent with the 15-minute onset, and 12-hour duration of action efficacy results from previous studies.
This is a 2020 ARVO Annual Meeting abstract.
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