The authors examined spectrophotometrically the ability of drugs to bind with ocular acid-insoluble melanin. Each drug, at 5 X 10(-5) M, was incubated at 37 degrees C for 8 hr with 4 mg of melanin in 20 mM potassium phosphate buffer (pH 7.4 and 8.0) or in 20 mM acetate buffer (pH 4.8). The authors findings showed that chloroquine, thioridazine, befunolol, pindolol, daunomycin, and 5-fluorouraci...