1417 Maintaining the sensitivity to timolol with a “pulsatile” therapy in primary open angle glaucoma. A 5 years follow up

ABSORPTION AND RELEASE OF MITOMYCIN-C BY “SPONGOSTAN FILM”. LARROSA JMl, FERRER J2, PINILLA 11, POLO VI, SANCHEZ Al, BUENO J’, HONRUBIA FMl. 1 Department of Ophthalmology, “Miguel Set-vet” Hospital. Zaragoza,(Spain) 2 Department of Microbiology, Puroose: To determine the Mitomycin-C (MMC) 0,4 mg./ml. absorption of spumous specimens of “Spongostan Film” (“Sp”) and their liberation rate. Methods: 1. Physical determination of amount of MMC per volume unit that “Sp” is able to absorb. (difference between dry weight and soaked weight) 2. Determination of MMC activity in known volumes of “Sp” after several times. of antimythotic release. (0, 1, 10, 30 seconds, I, 3, 5, IO, 15 and 30 minutes). Antibiotic activity of specimens is evaluated by mearls of bioassay in E. Coli ATCC 25922 Agar plates. Milimeters of inhibition of bacterial growth are related to pgr. of MMC activity according to a model equation obtained from known amounts of MMC. 3. “In viva” determination of remaining MMC activity of ‘IO “Sp” after 5 minutes of antimythotic release in a filtering surgery in the rabbit Results: The MMC maximum capacity of a 25 mm* X 6.5 mm. thick “Sp” is 33.96 pgrs.lcm2 (6.49 pgrs.125 mm2 of “Sp”). Biologic activity by bioassay is 8.24 pgrs. of MMC for a 25 mm* “Sp” (32.96 pgrs/cm2). “In vitro” release of MMC is gradual until 30 minutes (remaining pgrs.= 0.7!3). MMC “in viva” release by “Sp” after 5 minutes is 6.91 micrograms (remaining pgrs.=1.33). Conclusions: Bioassay is an easy and sensitive technique that permits evaluation of MMC activity. The MMC dosage calculation allows comparison among diferenl authors and study of doseeffect relationship.