Bimatoprost is an F-series prostaglandin (PG) analog which has been approved for use as an ocular hypotensive drug. Oxidation of the C-15 hydroxyl group and amide hydrolysis of Bimatoprost produces 15-keto-17-phenyl trinor PGF2α. 15-keto-17-phenyl trinor PGF2α is a potential metabolite of bimatoprost when administered to animals. 15-keto PG analogs are potential minor impurities in commercial preparations of their corresponding bulk drug compounds. Although much less potent that the parent compound, 15-keto PGs still retain the ability to produce a small but measurable decrease (1 mm Hg) in the intraocular pressure of normal cynomolgus monkeys when administered at a dose of 1 µg/eye. 15-keto Latanoprost (15-keto-17-phenyl-13,14-dihydro trinor PGF2α isopropyl ester) is a miotic in the normal cat eye, causing an 8 mm reduction in pupillary diameter at 5 µg/eye. Again, this is not as potent as many other F-type PGs; for example, PGF2α will produce this degree of miosis at a dose of less than 1 µg/eye.