A number of 17-phenyl trinor PGF2α derivatives have been approved for the treatment of glaucoma. Of these, the unsubstituted or meta-substituted aromatic derivatives are the most potent FP receptor agonists. 17-trifluoromethylphenyl trinor PGF2α bears an aromatic ring which is reminiscent of the trifluoromethyl-phenoxy ring of travoprost ((+)-fluprostenol isopropyl ester). As an ocular hypotensive agent, it would be expected that 17-trifluoromethylphenyl trinor PGF2α would act very much like the free acid of travoprost.