Latanoprost ethyl amide (Lat-NEt) is a latanoprost analog in which the C-1 carboxyl group has been modified to an N-ethyl amide. Prostaglandin esters have been shown to have ocular hypotensive activity. Prostaglandin N-ethyl amides were recently introduced as alternative prostaglandin ocular hypotensive prodrugs. Although it has been claimed that prostaglandin ethyl amides are not converted to the free acids in vivo, studies in our laboratories have shown that bovine and human corneal tissue converts the N-ethyl amides of various prostaglandins to the free acids with a conversion rate of about 2.5 μg g corneal tissue hr. Lat-NEt would be expected to show the typical intraocular effects of Latanoprost free acid, but with the much slower hydrolysis pharmacokinetics of the prostaglandin N-amides.
Prostaglandin F2α (PGF2α), acting through the FP receptor, causes smooth muscle contraction and exhibits potent luteolytic activity. 17-trifluoromethylphenyl trinor Prostaglandin F2α (17-trifluoromethylphenyl trinor PGF2α) is an analog of PGF2α that shares the meta-trifluoromethyl group of travoprost with the 17-phenyl trinor modification of latanoprost. It is anticipated to be a potent and selective agonist of the FP receptor, with potential applications in glaucoma and luteolysis. 17-trifluoromethylphenyl trinor PGF2α ethyl amide is a lipophilic analog of 17-trifluoromethylphenyl trinor PGF2α. Ethyl amides of PGs can serve as prodrugs, as they are hydrolyzed in certain tissues to generate the bioactive free acid.
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.
N-Desethyl Bimatoprost (17-phenyl trinor PGF2α amide) is an F-series PG analog in which the C-1 carboxyl group has been modified to an unsubstituted amide. PG esters have been shown to have ocular hypotensive activity. PG N-ethyl amides were recently introduced as alternative PG hypotensive prodrugs. Although it has been claimed that PG amides are not converted to the free acids in vivo, studies have shown that bovine and human corneal tissue converts the amides of various PGs to the free acids with a conversion efficiency of about 10-20% relative to the hydrolysis of isopropyl esters. 17-phenyl trinor PGF2α amide would be expected to show the typical intraocular effects of latanoprost, but with the much slower hydrolysis pharmacokinetics of the PG N-amides.
17-phenyl trinor PGF2α N-ethyl amide is an F-series prostaglandin analog which has been approved for use as an ocular hypotensive drug, sold under the Allergan trade name Bimatoprost. The N-ethyl amide prostaglandin prodrugs are converted to the active free acid more slowly than the analogous prostaglandin ester prodrugs such as latanoprost. This product is the isopropyl ester of the free acid prostaglandin which corresponds to Bimatoprost. The free acid, 17-phenyl trinor PGF2α, is a potent FP receptor agonist. In human and animal models of glaucoma, FP receptor agonist activity corresponds very closely with intraocular hypotensive activity. The 17-phenyl trinor PGF2α isopropyl ester derivative was examined for IOP-lowering activity during the development of latanoprost. At the dose of 3 μg eye in the monkey, 17-phenyl trinor PGF2α isopropyl ester was the most potent analog tested in reducing IOP, lowering the IOP 1.3 mm Hg below the level achieved by latanoprost. However, this derivative was also significantly more irritating to the eye than latanoprost.