TY - JOUR T1 - ETHYNODIOL DIACETATE METABOLITES IN HUMAN PLASMA JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 696 LP - 702 VL - 185 IS - 3 AU - C. E. COOK AU - AZIZ KARIM AU - JOYCE FORTH AU - MONROE E. WALL AU - R. E. RANNEY AU - RUBIN C. BRESSLER Y1 - 1973/06/01 UR - http://jpet.aspetjournals.org/content/185/3/696.abstract N2 - Human plasma metabolites of ethynodiol diacetate (3β,17β-diacetoxy-l7α-ethynyl-4-estrene) were identified by carrier addition analysis after oral administration of radiolabeled drug to a subject undergoing chronic treatment. Although a plasma half-life of 25 hours was observed for total radioactivity, the parent compound was not found 1 hour after administration. Carrier addition analysis showed the principal free plasma metabolite after 2 hours to be norethindrone (17α-ethvnyl-17 β-hydroxy-4-estren-3-one). Norethindrone was accompanied by its reduction products, 17α-ethynyl-5α-estrane-3α, 17β-diol and 17α-ethynyl-5β-estrane-3β,17β-diol. Two other isomeric reduction products of norethindrone, 17α-ethynyl-5β-estrane-3α, 17β-diol and 17α-ethvnyl-5α-estrane-3β,17β-diol, were also identified in the hydrolyzed plasma conjugate fraction, which made up the bulk of plasma radioactivity. © 1973 by The Williams & Wilkins Co. ER -