travoprost
"The isopropyl ester of prostaglandin F2alpha in which the pentyl group is replaced by a 3-(trifluoromethyl)phenoxymethyl group. A synthetic analogue of prostaglandin F2alpha, ophthalmic solutions of travoprost are used as a topical medication for controlling the progression of open-angle glaucoma and ocular hypertension, by reducing intraocular pressure. It is a pro-drug; the isopropyl ester group is hydrolysed by esterases in the cornea to the biologically active free acid, fluprostenol."