Aspect on Corneal Permeability of Bupranolol

Abstract

Because the cornea forms an important boundary tissue in the anterior eye portion, the corneal permeability of ophthalmic drugs is of great importance in drugs administered topically. To evaluate the intraocular penetration of bupranolol, an antiglaucoma ophthalmic solution, its in vitro corneal permeability was examined, using excised rabbit cornea mounted on the methacrylate chamber. Permeation time was carried out within 10-30 minutes at 35°. Permeability constants were calculated from measuring the initial amount of bupranolol (C0), the residual amount of bupranolol in the tear-side chamber (C1), the concentration in the aqueous-side chamber (C2), thickness of the cornea (Δχ) and corneal permeation area (A) after each permeation time. In both, tissue culture medium and ophthalmic solution, the constant of corneal permeable velocity (K) and permeability constant of the membrane (P) of bupranolol increased with permeation time, and those values did not depend on bupranolol concentration. The present results suggest that the bupranolol compound at the precorneal pocket penetrates into the intraocular area through the cornea.