Amniotic membrane, tear film, corneal, and aqueous levels of ofloxacin in rabbit eyes after amniotic membrane transplantation

Purpose. We evaluated ocular penetration and drug levels in tears after top ical ofloxacin instillation in rabbit eyes with amniotic membrane transplan tation (AMT). Methods. Forty-eight New Zealand White rabbits were used. In the first set of experiments, 24 rabbits (24 eyes) were divided into four g roups according to the epithelial removal or AMT. Topical ofloxacin was ins tilled four times every 15 minutes. One hour after the last eyedrop, the co ncentration of ofloxacin in the amniotic membrane, cornea, and aqueous humo r was evaluated. In the second set of experiments, 24 rabbits were divided into six groups according to AMT (transplantation of lyophilized or fresh a mniotic membrane) or duration of application. Ofloxacin ointment or two dro ps of ofloxacin were applied to the right eye, and then tear samples were c ollected after 0.5, 1, 2, 4, and 6 hours for the analysis of ofloxacin conc entration. Results. Mean ofloxacin concentrations in the cornea and aqueous humor were statistically higher in deepithelialized cornea regardless of A MT (p < 0.05). The mean tear levels of ofloxacin in the AMT groups were sta tistically higher than those in non-AMT groups (p < 0.05). There was no sta tistical significance in the tear level of ofloxacin between lyophilized am niotic membrane groups and fresh amniotic membrane groups nor between 1-hou r amniotic membrane-attached groups and 6-hour amniotic membrane-attached g roups. Conclusion. Amniotic membrane transplantation seems to interfere wit h the ocular penetration of topical ofloxacin in normal rabbit corneas but enhances ofloxacin penetration in corneas with epithelial defects. The oflo xacin level in tears was higher in eyes with AMT up to 1 hour after topical ofloxacin use. Therefore, it seems that amniotic membrane has some potenti al to act as an effective drug delivery system.