caa a22 4500 477057195 CHVBK 20180405111349.0 cr unu---uuuuu 170330e19960501xx s 000 0 eng 10.1007/s002280050098 doi (NATIONALLICENCE)springer-10.1007/s002280050098 Influence of repeated oral doses of ethinyloestradiol on the metabolic disposition of [13C2]-ethinyloestradiol in young women [Elektronische Daten] [W. Kuhnz, M. Hümpel, H. Biere, D. Gross] Objective: To examine the influence of daily oral administration of ethinyloestradiol on the total clearance of 13C-labeled ethinyloestradiol in women. Methods: 19, healthy, young women received a single IV dose of 0.06 mg 13C-ethinyloestradiol. Subsequently, they were treated with daily oral doses of 0.06 mg ethinyloestradiol for 8 days. On the last day of oral treatment, they received a further IV dose of 0.06 mg 13C-ethinyloestradiol. The pharmacokinetic parameters clearance, area under the serum level-time curve, terminal half-life, steady-state volume of distribution and mean residence time of 13C-ethinyloestradiol in each volunteer were evaluated after both IV doses, and the corresponding pairs of parameters were examined statistically for the significance of intraindividual differences. Results: Following the first (second) intravenous administration, the mean area under the curve was 2.54 (2.67) ng⋅h⋅ml−1. The terminal half-life and mean residence time were 9.7 (9.6) h and 10.5 (10.1) h, respectively. The steady-state volume of distribution was 4.3 (3.9) l⋅kg−1 and the clearance was 7.0 (6.6) ml⋅ min−1⋅kg−1. No significant difference was observed in any of these parameters between the first and the second IV doses of 13C-EE2. Conclusions: Since the clearance in particular remained unchanged after repeated oral administration of ethinyloetradiol, the hypothesis that ethinyloestradiol can inhibit its own metabolism in vivo can be rejected. Springer-Verlag Berlin Heidelberg, 1996 Key words Ethinyloestradiol nationallicence clearance nationallicence stable isotope nationallicence Kuhnz W. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut Hümpel M. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut Biere H. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut Gross D. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut https://doi.org/10.1007/s002280050098 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002280050098 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kuhnz W. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut NATIONALLICENCE 700 1- Hümpel M. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut NATIONALLICENCE 700 1- Biere H. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut NATIONALLICENCE 700 1- Gross D. Research Laboratories, Schering AG, D-13342 Berlin, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer