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 treatment for patients at high risk of failure after glaucoma filtration surgery. The purpose of this study is to compare the clinically used commercial solution of 5-FU with a suspension of 5-FU in a gel of 1% sodium 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 has been developed to evaluate the bioavailability of 5-FU. No purification of the samples was required before chromatography. Both vehicles led to the same mean concentrations of 5-FU in the aqueous humor at each observation time as confirmed by a t-test (p > 0.05 for all observation times). The bleb formed by the subconjunctival injection remained longer in SH-5-FU treated eyes(> 24 h) than in eyes having received the commercial 5-FU formulation (4 h). Eyes receiving the commercial formulation were more inflamed compared to those receiving 5-FU in SH. Although sodium hyaluronate gives the same bioavailability as that obtained with the commercial solution of 5-FU, it seems to be more suitable for the subconjunctival administration of 5-FU because this formulation is less inflammatory due to its physiological pH. Therefore, the SH-5-FU suspension could gain clinical attention in selected cases of glaucoma filtration surgery.