15(S)-15-methyl PGF2α methyl ester is a derivative of 15(S)-15-methyl PGF2α with increased membrane permeability.{4634,4635} Hydrolysis of the methyl ester in vivo releases the biologically active 15(S)-15-methyl PGF2α, which is a potent uterine stimulant and abortifacient.{4695,1608,1587}