15-keto-17-phenyl trinor Prostaglandin F2α

Bimatoprost is an F-series prostaglandin (PG) analog which has been approved for use as an ocular hypotensive drug.¹ Oxidation of the C-15 hydroxyl group and amide hydrolysis of Bimatoprost produces 15-keto-17-phenyl trinor PGF_2α. 15-keto-17-phenyl trinor PGF_2α 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.² 15-keto Latanoprost (15-keto-17-phenyl-13,14-dihydro trinor PGF_2α 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, PGF_2α will produce this degree of miosis at a dose of less than 1 μg/eye.

1. Cantor, L.B. Bimatoprost: a member of a new class of agents, the prostamides, for glaucoma management Expert Opin. Investig. Drugs 10,721-731(2001).
2. Stjernschantz, J., and Resul, B. Phenyl substituted prostaglandin analogs for glaucoma treatment Drugs Future 17(8),691-704(1992).