First Author: D.Muller USA
Co Author(s): R. Pertaub D. Usher E. Sherr M. Friedman P. Hersh
Purpose:
To determine the safety and diffusion characteristics of a trans-epithelial riboflavin formulation.
Setting:
Laboratory studies were undertaken at Avedro, Waltham, MA and Toxikon, Bedford, MA
Methods:
64 New Zealand Red rabbits (32M/32F) were divided into four groups. One eye was instilled with 40 microliter drops of riboflavin solution at 5 minute intervals for a total of 5 instillations with BSS rinse 5 minutes following final installation, the other eye served as control. 12 received transepithelial formulation of riboflavin containing 0.2% benzalkonium chloride (BAK), 20 received formulation containing 0.5% BAK, 20 received formulation containing 0.5% BAK and were immediately exposed to 5.4 j/cm2 dose of UVA, 12 received formulation containing 0.1% BAK. ½ of each group were observed for 1 day prior to necropsy. The other half were observed for 15 days prior to necropsy. Necropsy focused on both gross and histologic ocular effects of exposure. In a separate experiment a fluorescent dosimetry system which utilizes a UVA LED source, a digital micromirror device (DMD) and an imaging camera was used to measure the fluorescence of riboflavin through the cross-section of enucleated rabbit eyes using instillations of the transepithelial riboflavin containing 0%, 0.01%. 0.02% and 0.05% BAK (5 eyes each). The rate of riboflavin diffusion was measured.
Results:
Clinically, animals tolerated exposures well. Effects consisted of none to moderate redness, none to mild edema and/or none to mild discharge, resolving typically within 3 days of exposure. Incidence increased with increasing BAK concentration and exposure to UVA. Gross and histologic pathology will be discussed. The rate of riboflavin diffusion increased with increasing BAK concentration.
Conclusions:
The application of transepithelial riboflavin formulations, containing BAK concentrations of ?0.05%, result in mild, dose dependent, irritation which resolves clinically within 3 days. The use of these formulations provide for delivery of riboflavin to target tissue without mechanical removal of epithelium with a predictable rate of riboflavin diffusion. FINANCIAL DISCLOSURE?: ... gains financially from product or procedure presented, ... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... receives nonNomonetary benefits from a company producing, developing or supplying the product or procedure presented., ... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, ... is employed by a forNoprofit company with an interest in the subject of the presentation, ... has significant investment interest in a company producing, developing or supplying product or procedure presented
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