17-phenyl trinor Prostaglandin E2 ethyl amide

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 ?M 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.