Assay methodology for prednisolone, prednisolone acetate and prednisolone sodium phosphate in rabbit aqueous humor and ocular physiological solutions.

Prednisolone, prednisolone acetate and prednisolone sodium phosphate are glucocorticoids used for ocular, anti-inflammatory therapy. A reversed-phase high-performance liquid chromatographic assay using ultraviolet detection has been developed that affords baseline resolution of the above analytes in balanced salt solutions and rabbit aqueous humor. The drugs can be quantified at 0.025-0.05 micrograms/ml in the above matrices; 6 alpha-methylprednisolone is used as the internal standard. Both esters of prednisolone are vulnerable to chemical and enzymatic hydrolysis giving prednisolone. Analysis of aqueous humor samples shows prednisolone acetate penetrating/metabolizing primarily to prednisolone; prednisolone sodium phosphate penetrates the cornea giving the ester and alcohol.