Bioavailability and penetration of topical amphotericin B in the anterior segment of the rabbit eye.

The penetration of topical amphotericin B was studied in Dutch-belted rabbits using bioassay and radioassay techniques. Seven percent of total amphotericin B in the corneas, as measured by recovered 14-C, and 5% in the aqueous was in a bioactive form. Drug was not detectable by bioassay after single drop administration but after a loading dose approach, drug was present in therapeutic amounts. In inflamed corneas, a pass-through effect was noted with higher levels initially but rapid fall-off subsequently.