Elucidation of the pharmacokinetics of prednisone and prednisolone: elimination and the effect of estrogen
Several aspects of the pharmacokinetics of the interconvertible glucocorticoids prednisone and prednisolone have been studied. The pharmacokinetics of prednisolone were examined in postmenopausal women taking conjugated estrogens and age-matched control women. The subjects received iv bolus doses of 0.14 and 0.55 mg/kg prednisolone. Expected increases in clearance and volume of distribution with increasing dose were observed for total prednisolone in all subjects. At both doses, significant decreases in total and unbound prednisolone clearance were observed in the women taking estrogen compared to the controls. Volume of distribution was unchanged. The decreases in clearance are smaller than those observed in young women taking oral contraceptives indicating that factors other than estrogen administration may influence prednisolone clearance in oral contraceptive users. While the protein binding of prednisolone is well characterized, little is known about the protein binding of prednisone. Equilibrium dialysis employing (/sup 3/H)prednisone was used to study the binding of prednisone in human plasma containing endogenous hydrocortisone. Plasma was obtained from volunteers with normal and elevated transcortin binding capacities (CAP/sub T/). Prednisolone binding exhibits marked concentration dependence and sensitivity to CAP/sub T/. In contrast, prednisone binding is independent of concentration and CAP/sub T/.
- Research Organization:
- California Univ., San Francisco (USA)
- OSTI ID:
- 6646948
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ESTROGENS
BIOLOGICAL EFFECTS
PREDNISONE
BLOOD-PLASMA CLEARANCE
DYNAMIC FUNCTION STUDIES
GLUCOCORTICOIDS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
WOMEN
ADRENAL HORMONES
ANIMALS
CLEARANCE
CORTICOSTEROIDS
FEMALES
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
LABELLED COMPOUNDS
MAMMALS
MAN
ORGANIC COMPOUNDS
PREGNANES
PRIMATES
STEROID HORMONES
STEROIDS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques