PURPOSE: The authors investigated the aqueous and vitreous pharmacokinetics of mitomycin after postoperative topical administration in rabbits. METHODS: Filtration surgery was performed in one eye of each rabbit. On the first postoperative day, mitomycin solution (0.4 mg/ml) was administered by either topical drop or cellulose sponge in both eyes of each rabbit. Aqueous and vitreous paracenteses were performed at 0.25, 0.5, 1, 2, 3, and 4 hours thereafter. Three rabbits were tested at each time interval for each type of administration. RESULTS: After topical drop administration, the peak aqueous concentration was 0.03 +/- 0.02 microgram/ml (mean +/- standard error) in surgical eyes and 0.06 +/- 0.03 microgram/ml in control eyes. After sponge administration, the peak aqueous concentration was 0.10 +/- 0.03 microgram/ml in surgical eyes and 0.08 +/- 0.04 microgram/ml in control eyes. Peak aqueous concentrations from drop and sponge applications were achieved at 1 to 2 hours after administration. Vitreous levels were well below the concentration known to cause retinal toxicity at all time intervals tested. CONCLUSION: Postoperative topical administration of mitomycin was successful in delivering mitomycin into the aqueous humor of rabbit eyes. Alternative methods of mitomycin application from the currently popular intraoperative administration may be beneficial in situations in which mitomycin delivery across intact conjunctiva may be desirable.
PURPOSE: The authors investigated the aqueous and vitreous pharmacokinetics of mitomycin after postoperative topical administration in rabbits. METHODS: Filtration surgery was performed in one eye of each rabbit. On the first postoperative day, mitomycin solution (0.4 mg/ml) was administered by either topical drop or cellulose sponge in both eyes of each rabbit. Aqueous and vitreous paracenteses were performed at 0.25, 0.5, 1, 2, 3, and 4 hours thereafter. Three rabbits were tested at each time interval for each type of administration. RESULTS: After topical drop administration, the peak aqueous concentration was 0.03 +/- 0.02 microgram/ml (mean +/- standard error) in surgical eyes and 0.06 +/- 0.03 microgram/ml in control eyes. After sponge administration, the peak aqueous concentration was 0.10 +/- 0.03 microgram/ml in surgical eyes and 0.08 +/- 0.04 microgram/ml in control eyes. Peak aqueous concentrations from drop and sponge applications were achieved at 1 to 2 hours after administration. Vitreous levels were well below the concentration known to cause retinal toxicity at all time intervals tested. CONCLUSION: Postoperative topical administration of mitomycin was successful in delivering mitomycin into the aqueous humor of rabbit eyes. Alternative methods of mitomycin application from the currently popular intraoperative administration may be beneficial in situations in which mitomycin delivery across intact conjunctiva may be desirable.