In vitro Diffusion of Mitomycin-C into Human Sclera after Episcleral Application: Impact of Diffusion Time

• Published in: Experimental eye research Vol. 71; no. 5; pp. 453 - 457
• Main Authors: Georgopoulos, M., Vass, C., El Menyawi, I., Radda, S., Graninger, W., Menapace, R.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01-11-2000; Elsevier
• Subjects: Administration, Topical; Analysis of Variance; Animals; Biological and medical sciences; Chromatography, High Pressure Liquid; ciliary body; Diffusion; Eye; filtering surgery; glaucoma; Humans; Isotonic Solutions; Medical sciences; Mitomycin - administration & dosage; Mitomycin - pharmacokinetics; mitomycin-C; Nucleic Acid Synthesis Inhibitors - administration & dosage; Nucleic Acid Synthesis Inhibitors - pharmacokinetics; Pharmacology. Drug treatments; Rabbits; sclera; Sclera - metabolism; Sodium Chloride - administration & dosage; Therapeutic Irrigation; Time Factors; Trabeculectomy - methods; mitomycin-C; filtering surgery; sclera; ciliary body; glaucoma; Human; Eye; Visual system; Ciliary body; Antibiotic; Episcleral; Mitomycin; Diffusion; Sclera
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1006/exer.2000.0901

The purpose of this study was to investigate the impact of different diffusion times of mitomycin-C (MMC) on the intrascleral concentration vs depth profile of MMC in an experimental model. Scleral quadrants of eight human donor eyes were exposed to sponges soaked with MMC for an application time of 1min. After irrigation with 40ml saline, we allowed further diffusion of MMC in the sclera for 1, 5, 14 and 29min until the specimens were further processed. A central 8mm diameter scleral disk was horizontally dissected with a kryotome at −20°C. MMC concentrations of six layers of 140μ m thickness were analysed by means of high-performance liquid chromatography. The MMC concentrations (μ gg−1) of layer 1 were: 13.45±5.9 (mean±S.D. at 2min diffusion time), 7.6±2.5 (6min diffusion), 5.6±3.1 (15min diffusion) and 3.6±1.7 (30min diffusion). The corresponding MMC concentrations of layer 6 were: 0.61±0.48, 1.47±0.66, 1.83±0.42 and 2.98±0.97μ gg−1. The superficial concentration of intrascleral MMC decreased with increasing diffusion time, the deep concentrations increased. After 30min of diffusion time, equal concentrations of MMC were found in all layers. Even with current low-dose application regimens of MMC the concentrations in the inner side of the sclera rapidly increase beyond the limits of the therapeutic range. Owing to this fast diffusion of MMC, the only means of reducing ciliary body concentrations of MMC is to reduce the dose.