Evaluation of the behavior and efficacy of a biodegradable intraocular insert in an experimental model

Abstract

Cataract surgery results in rapid recovery, and its success is associated with postoperative medication. However, the indicated eye drops may cause adverse reactions. An alternative to avoid topical medication is the use of biodegradable intrasurgical implants of co-glycol polylactic acid (PLGA) containing moxifloxacin hydrochloride (MOX) and dexamethasone (DEX). Purpose: To evaluate the decay time, toxicity, and anti-inflammatory effects of a biodegradable intraocular PLGA implant containing MOX and DEX in an animal model.

11 New Zealand rabbits were used. All procedures followed CICUAL-approved guidelines (FCM-UNC). To analyze the degree of disintegration, weekly measurements of the implant placed in the anterior chamber of the eye (n=5) were performed. These weekly measurements included optical instruments with high magnification and inspections of intraocular toxic changes. Alternatively, an animal model of rabbits undergoing cataract surgery was used to evaluate the anti-inflammatory efficacy. These animals were divided into 2 groups: Group A: Eyes without implant (n=3) and group B: Eyes with implant (n=3). Subsequently, daily postoperative serial controls were performed with a slit lamp. This allowed us to determine the degree of aqueous humor opacity (flare) using a scale from 0 (no opacity) to 4 (severe opacity). All measurements were supported with digital images at high magnification.

In the first two weeks, the average weekly disintegration was about 50%. In the following week, the percentage was about 80%. Finally, in the fourth week, there were no more signs of the implant. No toxic changes were observed in the inner ocular compartments. There was a significant  difference between group A and group B regarding the decrease in postoperative inflammation scores: day 1: p=0.01, day 2 p=0.02; in the following days there was a difference between the groups, but it was not significant.

The implant causes a significant anti-inflammatory effect in a model of cataract surgery in rabbits without causing intraocular toxic reactions. The complete disintegration time of the implant is about 30 days.