Esterase distribution in the rabbit cornea and its implications in ocular drug bioavailability.

摘要: Being the major pathway by which topically applied ophthalmic drugs enter eye, cornea can control amount of active drug ultimately absorbed offering resistance to permeation and metabolizing during permeation. This research seeks determine esterase activity in two its component layers--epithelium stroma-endothelium--so as anticipate extent containing ester linkages will be metabolized transport. has been achieved incubating corneal homogenates albino pigmented rabbits various age groups with alpha-naphthyl acetate, model substrate, monitoring fluorescence intensity due alpha-naphthol a function time. The results indicate that: (1) epithelium is approximately twice that stroma-endothelium; (2) intact linearly related those (3) layers varies rabbit's strain. According these bulk esterase-mediated hydrolysis expected take place epithelium, so residence time this tissue have significant impact on ocular bioavailability.