Abstract
Purpose: :
Using an established rabbit toxicological model, this study compared in vivo the ocular toxicity of five topical intraocular pressure (IOP)-lowering agents: the commercial benzalkonium chloride (BAC)-containing solutions of 0.005% latanoprost, 0.004% travoprost, 0.03% bimatoprost (containing respectively 0.02%, 0.015%, 0.005% BAC), BAC-free 0.004% travoprost Z, and 0.005% latanoprost in a new cationic emulsion (LCEm) formulation.
Methods: :
Thirty adult male New Zealand albino rabbits were used in this study. They were randomly divided into five groups: 50 µl of each formulation were applied onto rabbit eyes 15 times at 5-min intervals. The ocular surface changes were investigated using slit-lamp examination, corneal in vivo confocal microscopy (IVCM), flow cytometry (FCM), and conjunctival impression cytology (IC).
Results: :
Antiglaucoma eye drops induced an ocular surface toxicity primarily related to the concentration of their common preservative BAC (latanoprost>travoprost>bimatoprost). LCEm did not induce obvious toxicity to rabbit ocular surface, just as BAC-free travoprost, by showing almost normal aspect of conjunctiva/cornea by clinical observation, CALT-IVCM analysis and IC evaluation.
Conclusions: :
These in vivo and ex vivo experimental toxicological studies confirmed the ocular surface toxicity of antiglaucomatous BAC-containing eye drop solutions. BAC-free cationic emulsion of latanoprost (LCEm) and travoprost Z were well tolerated and did not induce ocular surface damages. The IOP-lowering eye drop LCEmwill most likely have fewer ocular surface adverse effects than formulations containing preservative BAC.
Keywords: ocular irritancy/toxicity testing • inflammation • microscopy: confocal/tunneling