Heparin drug delivery system for prevention of posterior capsular opacification in rabbit eyes

Background: The aim of this study was to investigate the safety and efficacy of a heparin drug delivery system (HEP DDS) for prevention of posterior capsular opacification (PCO) in rabbits. Methods: Fifty New Zealand albino rabbits (50 eyes) undergoing phacoemulsification were equally divided into five groups receiving normal saline eye drops (group A), a carrier DDS implanted into the posterior chamber (group 13), 5% heparin eye drops (group C), a HEP DDS implanted subconjunctivally (group D) and a HEP DDS implanted into the posterior chamber (group E). All the 50 eyes were examined by slit-lamp microscopy. The heparin levels in blood and aqueous humor were measured, and the wet posterior capsules were weighed. Results: All eyes in groups A and B had PCO at 5-7 days, much earlier than in groups C, D and E. Two eyes in group C, three eyes in group D and six eyes in group E showed no signs of PCO throughout the 12-week study. The mean weight of wet posterior capsules from groups A-E was 157.919 mg, 160.091 mg, 81.114 mg, 71.827 mg and 19.984 mg respectively. The mean aqueous humor heparin level in groups C, D and E was 10.279 mug/ml, 13.246 mug/ml and 25.964 mug/ml respectively. Cell proliferation of the posterior capsules in group E was not active. The conjunctiva, cornea, iris, ciliary body and retina remained intact, and no significant toxic reactions were observed. No intraocular hemorrhage occurred during the follow-up. Conclusion: Implantation of a HEP DDS into the posterior chamber of experimental animals significantly maintained a higher heparin level in aqueous humor for a relatively long period of time. The findings indicate potential prevention of PCO with minimum toxic and side effects.