MITOMYCIN-C CONCENTRATION IN HUMAN AQUEOUS-HUMOR FOLLOWING TRABECULECTOMY

The aim of the study was to determine mitomycin-C (MMC) concentrations in human aqueous humour during trabeculectomy and to correlate anteri or chamber concentrations with method of application. MMC was applied intra-operatively by saturating sponges, ranging in size from 2 x 2 x 5 mm to 2 x 4 x 10 mm on dry cut, with 0.5 mg/ml MMC during trabeculec tomy for 3-5 minutes. Applications to episclera were made in 18 cases and to the scleral bed after scleral flap dissection in 9 cases. Aqueo us samples were collected by paracentesis with a 30 gauge needle 2-7 m inutes after removal of sponge and external irrigation. Aqueous MMC co ncentrations were determined by high-performance liquid chromatography . Aqueous MMC concentration in 27 samples ranged from below minimum de tectable concentration (less than 5 ng/ml) to 120.8 ng/ml. Mean aqueou s drug levels obtained when the applications were to the scleral bed w ere 35.65 +/- 39.17 ng/ml (range 5-120.8 ng/ml). Applications on episc lera gave mean aqueous concentrations of 4.98 +/- 9.11 ng/ml (range 0- 33.3 ng/ml). The difference was statistically significant (p = 0.004). There were no correlations between sponge size, time of MMC exposure and aqueous MMC level. In conclusion, MMC is detectable in aqueous hum our within minutes of external application and the aqueous concentrati on level is higher if the application is in the scleral bed than on th e episclera. Toxicity of the drug at this concentration range for corn eal endothelial cells needs further investigation via in vitro and cli nical studies.