ISSN:
1432-1041
Keywords:
Key words Ethinyloestradiol; clearance
;
stable isotope
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002280050098
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