Bimatoprost is the Allergan trade name for 17-phenyl trinor prostaglandin F2α ethylamide (17-phenyl trinor PGF2α ethylamide), an F-series PG analog which has been approved for use as an ocular hypotensive drug. Oxidation of the C-15 hydroxyl group produces 15-keto-17-phenyl trinor PGF2α ethylamide. 15-keto-17-phenyl trinor PGF2α ethylamide is a potential metabolite of 17-phenyl trinor PGF2α ethylamide when 17-phenyl trinor PGF2α ethylamide is administered to intact animals. No pharmacological studies on 15-keto-17-phenyl trinor PGF2α ethylamide have been reported.
AL 8810 is an 11β-fluoro analog of prostaglandin F2α (PGF2α) which acts as a potent and selective antagonist at the FP receptor. AL 8810 ethylamide is an analog of AL 8810 in which the C-1 carboxyl group has been modified to an N-ethylamide. This modification is analogous to the PG N-ethylamides, as typified by Bimatoprost, that have been introduced as alternative PG ocular hypotensive prodrugs. In contrast to AL 8810 which contracted the cat iris, AL 8810 ethylamide showed no contraction activity at concentrations up to 10-4 M and did not antagonize the activity of PGF2α-ethanolamide in this system.
Prostaglandin F2α (PGF2α), acting through the FP receptor, causes smooth muscle contraction and exhibits potent luteolytic activity. Both 17-phenyl trinor PGF2α and 16-phenoxy tetranor PGF2α are metabolically stable analogs of PGF2α and potent agonists for the FP receptor. 17-phenoxy trinor PGF2α ethylamide is a lipophilic analog of 17-phenoxy trinor PGF2α . Ethylamides of PGs serve as prodrugs, as they are hydrolyzed in certain tissues to generate the bioactive free acid.
Latanoprost ethylamide (Lat-NEt) is a latanoprost analog in which the C-1 carboxyl group has been modified to an N-ethylamide. Prostaglandin esters have been shown to have ocular hypotensive activity. Prostaglandin N-ethylamides were recently introduced as alternative prostaglandin ocular hypotensive prodrugs. Although it has been claimed that prostaglandin ethylamides are not converted to the free acids in vivo, studies in our laboratories have shown that bovine and human corneal tissue converts the N-ethylamides 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.
17-phenyl trinor PGE2 ethylamide is derived from 17-phenyl trinor PGE2, a synthetic analog of PGE2 that acts as an agonist of EP1 and EP3 receptors in mice (Ki = 14 and 3.7 nM, respectively) and EP1, EP3, and EP4 in rats (Ki = 25, 4.3, and 54 nM, respectively). 17-phenyl trinor PGE2 causes contraction of guinea pig ileum at a concentration of 11 μM and is 4.4 times more potent than PGE2 as an antifertility agent in hamsters. Modification of the C-1 carboxyl group to an ethylamide serves to increase lipid solubility, thereby improving uptake into tissues and further lowering the effective concentration. Ethylamide groups are then removed by amidases, regenerating the active free acid.
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 ethylamide is a lipophilic analog of 17-trifluoromethylphenyl trinor PGF2α. Ethylamides of PGs can serve as prodrugs, as they are hydrolyzed in certain tissues to generate the bioactive free acid.
Prostaglandin F2αethylamide (PGF2α-NEt), a PGF2α analog featuring an N-ethylamide modification at the C-1 carboxyl group, possesses ocular hypotensive activity similar to PG esters. Introduced as alternative prostaglandin ocular hypotensive prodrugs, PGF2α-NEt and other PG N-ethylamides, contrary to claims of not converting to free acids in vivo, have been demonstrated by our laboratory studies to undergo conversion by bovine and human corneal tissue into the respective free acids at a rate of approximately 2.5 µg g corneal tissue hr. This suggests PGF2α-NEt is expected to elicit typical PGF2α free acid intraocular effects, albeit with slower hydrolysis kinetics characteristic of PG N-amides.