Ocular Absorption of Sulfonamide Derivatives After Local Application.

It has been reported previously1, 2 that sulfanilamide and sulfapyridine after local application to the eyes of experimental animals are absorbed in greater amounts by ocular tissues and fluids than occurs when these agents are administered orally.3-7 The ocular absorption of sulfathiazole has recently been studied by Bellows and Chinn.8 Dogs given 0.2 g per kg of the drug, which was dissolved in HCl before administration, after 4 hours developed blood concentrations of 7.4 mg %. The amounts of sulfathiazole found in ocular tissues and fluids were: sclera 10.4, conjunctiva 8.4, chorioretinal layers 4.9, cornea 2.0, vitreous humor 0.9, aqueous humor 0.4, and lens 0 mg %. When an aqueous suspension of a similar dose of sulfathiazole was given orally the concentrations were considerably lower: blood 1.7, conjunctiva 2.9, chorioretinal layers 1.7, aqueous humor 0.3, vitreous humor 0.2 and lens and cornea 0 mg %. Similar results have been reported on cats by Scheie and Sounders,9 who found that a very small am...