SODIUM HYALURONATE AS A VEHICLE FOR AN IMPROVED TOLERANCE OF 5-FLUOROURACIL ADMINISTERED SUBCONJUNCTIVALLY TO RABBITS

5-Fluorouracil (5-FU) is gaining clinical interest as an adjunct treat ment for patients at high risk of failure after glaucoma filtration su rgery. The purpose of this study is to compare the clinically used com mercial solution of 5-FU with a suspension of 5-FU in a gel of 1% sodi um hyaluronate (SH) for the subconjunctival injection of a 10 mg dose in healthy rabbits. The commercial solution has a pH of 9.0, which is irritant for the eye, and the gel of sodium hyaluronate has a pH of 7. 4. An HPLC method for the quantitation of 5-FU in the aqueous humor ha s been developed to evaluate the bioavailability of 5-FU. No purificat ion of the samples was required before chromatography. Both vehicles l ed to the same mean concentrations of 5-FU in the aqueous humor at eac h observation time as confirmed by a t-test (p > 0.05 for all observat ion times). The bleb formed by the subconjunctival injection remained longer in SH-5-FU treated eyes(> 24 h) than in eyes having received th e commercial 5-FU formulation (4 h). Eyes receiving the commercial for mulation were more inflamed compared to those receiving 5-FU in SH. Al though sodium hyaluronate gives the same bioavailability as that obtai ned with the commercial solution of 5-FU, it seems to be more suitable for the subconjunctival administration of 5-FU because this formulati on is less inflammatory due to its physiological pH. Therefore, the SH -5-FU suspension could gain clinical attention in selected cases of gl aucoma filtration surgery.