13,14-dihydroProstaglandinF2α (13,14-dihydro PGF2α) is the analog of PGF2α which has no unsaturation in the lower side chain. It causes luteolysis in hamsters with a potency five times higher than PGF2α. The ED50 value for 13,14-dihydro PGF2α as a luteolytic agent in hamsters is 1.5 µg 100 g.[1]
A number of 17-phenyl trinor prostaglandinF2α(17-phenyl trinor PGF2α) derivatives have been approved for the treatment of glaucoma.1,2,3Of these, the ones wherein the 13,14-double bond has been hydrogenated retain relatively good potency, but show a significantly reduced incidence of local irritant side effects.417-trifluoromethylphenyl-13,14-dihydro trinor PGF2αbears 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-13,14-dihydro trinor PGF2αwould act very much like the free acid of latanoprost.
11β-13,14-Dihydro-15-keto PGF2α, a PGD2 metabolite in the 15-hydroxy PGDH pathway, is formed in human males upon infusion or inhalation of tritiated PGD2, with peak plasma levels of both 11β-PGF2α and 11β-13,14-dihydro-15-keto PGF2α observed within 10 minutes. In human lung homogenates, PGD2 is metabolized firstly to 11β-PGF2α and subsequently to 11β-15-keto-PGF2α in the presence of NAD+, but not to 11β-13,14-dihydro-15-keto PGF2α. Conversely, guinea pig liver and kidney homogenates can metabolize PGD2 to 11β-13,14-dihydro-15-keto PGF2α via 11β-PGF2α, with both NAD+ and NADP+ being requisite for this conversion.
8-iso-13,14-dihydro-15-keto ProstaglandinF2α (8-iso-13,14-dihydro-15-keto PGF2α) is a metabolite of the isoprostane, 8-isoprostane (8-iso PGF2α), in rabbits, monkeys and humans. 8-iso PGF2α is a PG-like product of non-specific lipid peroxidation. In both humans and monkeys, exogenously infused 8-isoprostane is converted primarily to metabolites having 2 or 4 carbon atoms removed from the top side chain by β-oxidation. A similar pattern is observed when tritiated 8-isoprostane is infused into rabbits. Early in the infusion (within 10 minutes) 8-iso-13,14-dihydro-15-keto PGF2α was a significant component of the metabolite profile, which was comprised mostly of dinor 8-isoprostane metabolites. 8-iso-13,14-dihydro-15-keto PGF2α weakly inhibits the U-46619 or collagen-induced aggregation of human platelets, although a number of the E-series isoprostanes are much more potent in this assay.
Latanoprost, the isopropyl ester of 17-phenyl-13,14-dihydroprostaglandinF2α, serves as a prodrug for the free acid form, a potent FP receptor agonist in the eye. Isopropyl 5-(diphenylphosphoryl)pentanoate may exist as a potential trace impurity in commercial latanoprost preparations.