An in vitro comparison of the permeability of prednisolone, prednisolone sodium phosphate, and prednisolone acetate across the NZW rabbit cornea.

Controversy and ambiguity in the literature concerning the corneal penetration of prednisolone acetate over Prednisolone Sodium phosphate in NZW rabbits has recently prompted comparative studies using specific chromatographic assays. In vitro, corneal penetration studies were performed using the Ussing Chambers to compare the permeability and flux of both esters and prednisolone at 0.5% using a reversed phase HPLC-UV assay. Chromatograms of samples from the receiver chambers show primarily the presence of prednisolone from both esters; only prednisolone phosphate penetrated the cornea intact. Flux measurements were similar for prednisolone and both salt forms in terms of the metabolite prednisolone. Permeability coefficient calculations give the relative comparison: prednisolone acetate greater than prednisolone greater than prednisolone sodium phosphate.