Development and application of a radioimmunoassay of the new progestagen gestodene.
A radioimmunoassay for the determination of gestodene (17-ethinyl-13-ethyl-17 beta-hydroxy-4,15-gonadien-3-one) in human plasma is described with regard to procedure, specificity, accuracy and reproducibility. Antiserum was raised against gestodene-3-O-(carboxymethyl)oxime-BSA in rabbits and [9,11-3H]-gestodene tracer was used with a specific radioactivity of 2.16 TBq/mmol. The final antiserum dilution was 1: 200,000. RIA was performed according to routine methods using diethylether plasma extracts and the charcoal separation technique. Cross-reactivity of antiserum with cortisol, 17 beta-estradiol, progesterone, testosterone and ethinylestradiol was less than 0.03%; levonorgestrel exhibited a 5% cross-reactivity. No cross-reactivity with metabolites of gestodene or ethinylestradiol was found. Accuracy and precision of the assay were tested using human plasma samples spiked with 1, 5 and 10 ng/ml gestodene. Accuracy was within 94 to 104% of the nominal values. Within-assay and between-assay coefficients of variation were in the range of 4.7-6.5% and 10.3-13.1%, resp. This RIA was used to follow plasma gestodene levels after single oral administration of 75 micrograms of gestodene combined with 30 micrograms ethinylestradiol as tablet and coated tablet in a cross-over design in 6 female test subjects. Plasma gestodene levels were equivalent after both treatments.
Research Laboratories of Schering AG, Berlin, West Germany, FRG.
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Nieuweboer
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Tack
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Täuber
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Hümpel
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Wendt
D000704:Analysis of Variance; D002851:Chromatography, High Pressure Liquid; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D003429:Cross Reactions; D004997:Ethinyl Estradiol / Q000008:administration & dosage / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007106:Immune Sera; D009652:Norpregnenes / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D011372:Progestins / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D011863:Radioimmunoassay; D013810:Therapeutic Equivalency
D003278:Contraceptives, Oral, Hormonal; D007106:Immune Sera; D009652:Norpregnenes; D011372:Progestins; C033273:Gestodene; D004997:Ethinyl Estradiol