Estrogens, conjugated EUROPEAN PHARMACOPOEIA 8.0 – impurities B, C, D, E, F, G: for each impurity, not more than 0.5 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent); – unspecified impurities:foreachimpurity,notmorethan 0.1 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.10 per cent); E. estra-1,3,5(10)-triene-3,16α,17α-triol (17-epi-estriol), – sum of impurities other than A: not more than the area of the principal peak in the chromatogram obtained with reference solution (b) (1 per cent); – disregard limit: 0.05 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.05 per cent). F. estra-1,3,5(10)-triene-3,16β,17β-triol (16-epi-estriol), Loss on drying (2.2.32): maximum 0.5 per cent, determined on 1.000 g by drying in an oven at 105 °C for 3 h. ASSAY Dissolve 25.0 mg in ethanol (96 per cent) R and dilute to 50.0mLwiththesamesolvent.Dilute10.0mLofthis solution to 50.0 mL with ethanol (96 per cent) R.Measurethe absorbance (2.2.25)attheabsorptionmaximumat281nm. G. estra-1,3,5(10)-triene-3,16β,17α-triol (16,17-epi-estriol), Calculate the content of C18H24O3 taking the specific absorbance to be 72.5. IMPURITIES Specified impurities: A, B, C, D, E, F, G. Other detectable impurities (the following substances would, H. 3,16α-dihydroxyestra-1,3,5(10)-trien-17-one, if present at a sufficient level, be detected by one or other of the tests in the monograph. They are limited by the general acceptance criterion for other/unspecified impurities and/or by the general monograph Substances for pharmaceutical use (2034). It is therefore not necessary to identify these impurities for demonstration of compliance. See also 5.10. Control of impurities in substances for pharmaceutical use):H,I. I. 3-hydroxy-17-oxa-D-homoestra-1,3,5(10)-trien-17a-one. 01/2008:1512 ESTROGENS, CONJUGATED Estrogeni coniuncti A. estra-1,3,5(10),9(11)-tetraene-3,16α,17β-triol (9,11-didehydroestriol), B. 3-hydroxyestra-1,3,5(10)-trien-17-one (estrone), C18H21O5NaS + C18H19O5NaS Mr 372.4 + 370.4 DEFINITION Mixture of various conjugated forms of estrogens obtained from the urine of pregnant mares or by synthesis, dispersed in asuitablepowdereddiluent. The 2 principal components are 17-oxoestra-1,3,5(10)- trien-3-yl sodium sulfate (sodium estrone sulfate) and C. 3-methoxyestra-1,3,5(10)-triene-16α,17β-diol (estriol 17-oxoestra-1,3,5(10),7-tetraen-3-yl sodium sulfate (sodium 3-methyl ether), equilin sulfate). Concomitants are sodium 17α-estradiol sulfate, sodium 17α-dihydroequilin sulfate and sodium 17β-dihydroequilin sulfate. Content (percentages related to the labelled content): – sodium estrone sulfate: 52.5 per cent to 61.5 per cent; – sodium equilin sulfate: 22.5 per cent to 30.5 per cent; – sodium 17α-estradiol sulfate: 2.5 per cent to 9.5 per cent; – sodium 17α-dihydroequilin sulfate: 13.5 per cent to 19.5 per D. estradiol, cent; 2174 See the information section on general monographs (cover pages).