title: Collaborative study of an assay for progestational steroids in individual contraceptive tablets.
abstract: A single tablet assay method has been developed for determining norethindrone, norethynodrel, and norgestrel in commercial contraceptive tablets. The steroid is separated from the tablet constituents on a diatomaceous earth column, the chloroform eluate is reacted with isonicotinic acid hydrazide, and the steroid is determined by colorimetry. Norethynodrel is isomerized to a conjugated ketosteroid before the colorimetric determination. Fourteen laboratories collaboratively tested the method. The average recoveries in 3 brands of tablets were as follows: 102.6% for the sample labeled as containing 0.35 mg norethindrone/tablet, 99.4% for the 2.5 mg norethynodrel/tablet, and 98.2% for the 0.5 mg norgestrel/tablet. The assay method has been adopted as official first action.
mesh_terms: D003277:Contraceptives, Oral, Combined / Q000032:analysis; D008722:Methods; D009640:Norethindrone / Q000032:analysis; D009641:Norethynodrel / Q000032:analysis; D009644:Norgestrel / Q000032:analysis; D011372:Progestins / Q000032:analysis*; D013607:Tablets / Q000032:analysis
chemical_list: D003277:Contraceptives, Oral, Combined; D011372:Progestins; D013607:Tablets; D009644:Norgestrel; D009641:Norethynodrel; D009640:Norethindrone