The corneal and aqueous humor steroid concentrations produced by topical application of 0.1% carbon 14, ring-labeled preparations of three dexamethasone derivatives in petrolatum ointment base (dexamethasone sodium phosphate, acetate, and free alcohol) were determined. In both the inflamed and uninflamed eye with intact corneal epithelium, the acetate derivative of dexamethasone produced the highest concentration in cornea and aqueous humor. In the absence of corneal epithelium, the phosphate derivative achieved the highest concentration in both locations.
Kupferman A, Pratt MV, Suckewer K, Leibowitz HM. Topically Applied Steroids in Corneal DiseaseIII. The Role of Drug Derivative in Stromal Absorption of Dexamethasone. Arch Ophthalmol. 1974;91(5):373-376. doi:10.1001/archopht.1974.03900060385008