Comparative bioavailability of orally and vaginally administered progesterone

Area of Science:

• Pharmacokinetics
• Endocrinology
• Reproductive Health

Background:

• Progesterone (P) is a crucial hormone in the female reproductive system.
• Understanding its pharmacokinetics is vital for effective therapeutic applications.
• Comparing different administration routes can optimize treatment efficacy.

Purpose of the Study:

• To investigate the pharmacokinetics of progesterone (P).
• To compare the bioavailability of orally versus vaginally administered progesterone.
• To evaluate P pharmacokinetics in healthy premenopausal female volunteers.

Main Methods:

• Randomized crossover design comparing oral P (200 mg micronized) and vaginal P (400 mg pessary).
• Ten healthy premenopausal female volunteers participated.
• Plasma P levels were measured by radioimmunoassay.

Main Results:

• Peak plasma P concentrations varied significantly between oral and vaginal routes.
• Considerable interindividual variation in P levels was observed.
• Area under the plasma concentration-time curve (AUC) was not significantly different between the two formulations, indicating similar overall bioavailability.

Conclusions:

• Oral and vaginal progesterone formulations demonstrated comparable bioavailability.
• The findings support the use of both oral and vaginal routes for progesterone administration based on pharmacokinetic profiles.