Aqueous and Vitreous Concentration of Mitomycin C Administered Topically after Holmium Laser Sclerostomy in Rabbits

ABSTRACT

Mitomycin C is an antibiotic isolated from the broth of Streptomyces caespitosus which has been used as the adjunctive drug to reduce the fibroblast proliferation. Holmium laser sclerostomy can minimize conjunctival damage. We examined pharmacokinetics of mitomycin C following topical administration. Holmium laser sclerostomy was performed on one eye of each 15 rabbits and the other eye was served as a control. Next day, mitomycin C solution(0.4mg/ml) was administered by topical drops in both eyes of each rabbit. The concentrations of mitomycin C in the aqueous and the vitreous compartments of operated and control eyes were determined by HPLC at 0.5, 1, 2, 3, 6 hours after topical administration. The peak aqueous concentration was 0.07 microgram/ml in operated eyes and 0.06 microgram/ml in control eyes. The peak vitreous concentration was 0.10 microgram/ml in operated eyes and 0.09 microgram/ml in control eyes. The levels of detected mitomycin C at all time intervals were higher than the IC50(0.002 microgram/ml) for the inhibition of conjunctival fibroblast proliferation. These results suggest that topical mitomycin C easily crosses the intact and minimally damaged conjunctiva and therefore increases the success rate of Holmium laser sclerostomy.