du-41164 du-41164 du-41164, also known as 1,2β-methylene-6-fluoro-17α-acetoxy-δ6-retroprogesterone, is a progestin which was developed by philips-duphar in the 1970s and was never marketed. it is a combined derivative of 17α-hydroxyprogesterone and retroprogesterone. the drug shows extremely high potency as a progestogen in animals; it was reported to possess 500 times the affinity of progesterone for the progesterone receptor expressed in rabbit uterus (ki = 0.87 pm and 0.41 nm, respectively), and showed 600 times the progestogenic potency of subcutaneous progesterone when given orally in animals. the affinity of du-41164 for the progesterone receptor was described in 1974 as "probably the highest reported for any steroid-receptor interaction". the drug showed no androgenic, anabolic, antiandrogenic, estrogenic, or corticosteroid activity in animals. although highly potent in animals, du-41164 produced little or no progestogenic effect at dosages of 50 and 200 µg/day in women, suggesting major species differences. a closely related compound, du-41165, has been developed as a photoaffinity label for the progesterone receptor. du-41164clinical dataother names1,2β-methylene-6-fluoro-17α-acetoxy-δ6-retroprogesterone; 6-fluoro-17α-hydroxy-1,2β-methylene-9β,10α-pregna-4,6-diene-3,20-dione 17α-acetate; 6-fluoro-1,2β-methylene-3,20-dioxo-9β,10α-pregna-4,6-dien-17α-yl acetate; (1α,2α,9β,10α)-17-acetoxy-6-fluoro-1,2-dihydro-3'h-cyclopropapregna-1,4,6-triene-3,20-dioneroutes ofadministrationby mouthdrug classprogestin; progestogenidentifiers iupac name (2as,3ar,3br,3cr,5as,6r,8as,8br)-6-acetyl-10-fluoro-3b,5a-dimethyl-2-oxo-2,2a,3,3a,3b,3c,4,5,5a,6,7,8,8a,8b-tetradecahydrocyclopentacyclopropaphenanthren-6-yl acetate cas number34542-22-8 ypubchem cid193715chemspider168113unii38jxq87fepcomptox dashboard (epa)dtxsid00956058 chemical and physical dataformulac24h29fo4molar mass400.490 g·mol−13d model (jsmol)interactive image smiles cc(=o)1(cc21(cc32c=c(c4=cc(=o)5c534c)f)c)oc(=o)c inchi inchi=1s/c24h29fo4/c1-12(26)24(29-13(2)27)8-6-16-14-10-20(25)19-11-21(28)15-9-18(15)23(19,4)17(14)5-7-22(16,24)3/h10-11,14-18h,5-9h2,1-4h3/t14-,15-,16-,17+,18+,22-,23+,24-/m0/s1key:wjshhkqekqvlop-qhaundhqsa-n