Gracial ProdMonograph_cover - epgonline.org

Pharmacokinetics
ENG mainly
bound to
albumin and
SHBG
2.2 Ethinylestradiol (EE)
Following oral administration of Gracial, ethinylestradiol (EE) is
absorbed within 1.5 hours (Jung-Hoffman et al 1992) and
then distributed throughout the body. The absolute
bioavailability of EE after multiple dosing of a DSG/EE
combination has been calculated as approximately 59% (Back
et al 1987). Plasma EE is 98.5% protein bound, almost
entirely to albumin (Kuhl 1990).
The metabolism of EE involves cytochrome P450-mediated
hydroxylation, with 2-hydroxy-EE and 2-methoxy-EE as the
major metabolites (Purba et al 1987).
Half-life EE
29 hours
EE is eliminated from the body principally as conjugated
metabolites and the elimination half-life has been calculated
at about 29 hours (Bergink et al 1990). Excretion occurs via
urine and feces at a ratio of 1:1.6 (Speck et al 1976).
EE pg/ml)
100
50
Day 7
2 4 6 8 12 24 h
EE (pg/ml)
100
50
Day 22
2 4 6 8 12 24 h
Fig. 5: Ethinylestradiol serum concentration on days
7 and 22 of Gracial administration
Jung-Hoffmann et al 1992
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