17-Phenyl trinor Prostaglandin E2 (17-phenyl trinor PGE2) is a synthetic analog of PGE2, functioning as an agonist at the EP1 and EP3 receptors. It induces contraction of the guinea pig ileum at a 11 µM concentration and displays slightly less potency than PGE2 in stimulating the gerbil colon and rat uterus. Notably, with an ED50 value of 350 µg/kg, 17-phenyl trinor PGE2 exhibits 4.4 times greater antifertility efficacy in hamsters compared to PGE2.
17-phenyl trinor PGE2 ethyl amide 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 ethyl amide serves to increase lipid solubility, thereby improving uptake into tissues and further lowering the effective concentration. Ethyl amide groups are then removed by amidases, regenerating the active free acid.
9-deoxy-9-methylene-16,16-dimethyl Prostaglandin E2 (Meteneprost) is a potent analog of prostaglandin E2 with an extended half-life in vivo. In combination with various other prostaglandin derivatives, it results in the termination of first trimester pregnancy in monkeys. A single intramuscular injection containing 0.5 mg of meteneprost and 7.5 mg of 17-phenyl trinor PGF1α is very effective in terminating early pregnancy. This prostaglandin mixture is ineffective on monkeys in their third trimester of pregnancy. Meteneprost, when compared to PGE2 and PGF1α, in monkey and rat, does not result in unwanted side effects such as fever or gastrointestinal problems.