RESUMO
UNLABELLED: The concentration of the antitumor antibiotic mitomycin (CAS 50-07-7, mitomycin C, MMC), used in ophthalmic surgery for its antiproliferative effects, was measured in the aqueous humor of 7 glaucoma patients undergoing trabeculectomy. Sponges soaked with MMC-solution (100 microliters of MMC-solution 0.2 mg/ml: 20 micrograms) were applied intraoperatively on the scleral flap for 5 min. 100 to 200 microliters of aqueous humor were drawn with a needle 10 min following the end of topical MMC-treatment. Samples were assayed for MMC using a reverse-phase HPLC-system with ultraviolet detection (C18-column, elution: phosphate buffer (0.01 mol/l, pH: 6.5): methanol, v:v = 70:30, 365 nm). Swabs were extracted in phosphate-buffer (0.1 mol/l, pH: 7.0) before HPLC-analysis. External calibration was used for MMC quantitation. Quantitation limit was 10 ng/ml. In all aqueous humor samples MMC-concentration was below 10 ng/ml. MMC in the swabs amounted to 37% of the MMC amount applied. CONCLUSION: After intraoperative topical application, the MMC concentration in the aqueous humor of patients is very low. The substantial loss of MMC from the swabs used for the topical MMC-treatment suggests 1. rapid systemic absorption of MMC and/or 2. a loss through irrigation of the operative field following topical MMC-application.
