In vitro study on corneal permeability to bunazosin.

Corneal permeability of bunazosin, one of the alpha-adrenergic receptor antagonists, was investigated in vitro using excised rabbit cornea mounted on a corneal permeability apparatus, and the enhancing effects of various acids on the permeability of bunazosin were evaluated. Caprylic and capric acid elevated octanol/water partition coefficient of bunazosin, and corneal permeability was increased, probably as a result of ion-pair formation between them. Neither bunazosin, these acids, or the ion-pair caused corneal swelling. These acids, in contrast, had little effect on the partition of pilocarpine, or on corneal permeability.