Fluocortolone: pharmacokinetics and effect on plasma cortisol level.

Area of Science:

• Pharmacology
• Endocrinology
• Clinical Pharmacy

Background:

• Fluocortolone is a corticosteroid with potential effects on the hypothalamic-pituitary-adrenal (HPA) axis.
• Understanding its pharmacokinetics is crucial for determining appropriate dosing and predicting its impact on endogenous cortisol production.

Purpose of the Study:

• To investigate the pharmacokinetics of fluocortolone after oral administration in healthy adults.
• To evaluate the dose-dependent effects of fluocortolone on plasma cortisol levels and adrenal suppression.

Main Methods:

• Oral administration of fluocortolone (20, 50, 100 mg) to 9 healthy adults.
• Simultaneous measurement of fluocortolone and cortisol plasma concentrations using High-Performance Liquid Chromatography (HPLC) with UV detection.
• Analysis of pharmacokinetic parameters including peak plasma levels, half-life, volume of distribution, and oral clearance.

Main Results:

• Fluocortolone was rapidly absorbed, with peak plasma levels achieved within 1.4-2.1 hours.
• Peak plasma concentrations and area under the curve increased proportionally with dose (199, 419, 812 ng/ml for 20, 50, 100 mg).
• Pharmacokinetic parameters (half-life, volume of distribution, oral clearance) were dose-independent, with a half-life of 1.76 hours. Adrenal suppression was dose-dependent, with maximum suppression at 8 hours. Significant cortisol suppression at 24 hours was observed only with the 100 mg dose.

Conclusions:

• Oral fluocortolone exhibits dose-proportional pharmacokinetics in healthy adults.
• The intensity and duration of HPA axis suppression are directly related to the fluocortolone dose.
• A 100 mg dose of fluocortolone is required to achieve significant cortisol suppression at 24 hours, indicating a clear dose-response relationship for adrenal suppression.