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

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.

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 B), 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.

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 microg/ml, 13.246 microg/ml and 25.964 microg/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.

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.