New drug delivery system for corneal administration of mitomycin-C

To develop a new corneal release system to deliver optimum amounts of mitomycin-C (MMC) during the perioperative period of photorefractive keratectomy (PRK).

Ophthalmos S/A, São Paulo, Brazil.

Experimental study.

An in vitro experimental design was developed for studying a new MMC delivery system at a drug concentration of 0.02%. Whatman sterile filter paper disks with a diameter of 8.0 mm were impregnated with MMC solution. After drying, the disks were placed on agar plates seeded with Staphylococcus epidermidis; this was followed by instillation of a drop of sterile water. After 1 minute, the disks were removed and the plates were incubated for 48 hours at 35°C. The mean volume of the drops delivered from regular eyedrop bottles was determined, and the inhibition zone (in millimeters) was correlated with the amount of MMC loaded onto the disks.

Analysis of the inhibition zones produced by MMC indicated that 16 μg was the optimum dose to be incorporated in the disks. The mean volume of a drop delivered from eyedrop bottles was 37.7 μL. One minute after the application of a single drop of a balanced salt solution, the system released an adequate concentration of MMC for PRK.

A new delivery system for MMC was successfully developed for application during photorefractive keratectomy.

Dr. de Souza Lima Filho is the managing director of Ophtalmos S/A. Drs. de Souza Lima Filho, Irochima Pinheiro, and Oréfice have exclusive rights to intellectual property of this invention secured by a patent application filed with the Instituto Nacional da Propriedade Industrial.