It has been shown that the sulfonamide compounds with the exception of sulfanilamide penetrate the cornea poorly.1 Judging from the findings of Swan and White,2 we may assume that this poor penetration is due to the polar nature of the drugs. Further, the concentrations reached in the ocular tissues and fluids when sulfathiazole (2-[paraaminobenzenesulfonamido]-thiazole), sulfadiazine (2-[paraaminobenzenesulfonamido]-pyrimidine) and sulfapyridine (2-[paraaminobenzenesulfonamido]-pyridine) are administered orally or locally fall short of the values believed to be necessary for therapeutic effectiveness.
Boyd3 and von Sallmann,4 using sulfathiazole and sulfadiazine, respectively, increased the penetration through the cornea by means of iontophoresis. With this method the concentration of the drugs in the corneal tissues and aqueous humor increased three to fifteen times over the values obtained with the corneal bath alone.
One of us (J. B.5) recently mentioned that a marked increase in the penetrability of the sulfonamide compounds may be obtained
BELLOWS JG, GUTMANN M. APPLICATION OF WETTING AGENTS IN OPHTHALMOLOGYWITH PARTICULAR REFERENCE TO SULFONAMIDE COMPOUNDS. Arch Ophthalmol. 1943;30(3):352–357. doi:10.1001/archopht.1943.00880210076007