GynProgest 200 mg Mechanism of Action

Pharmacotherapeutic group: Sex hormones and modulators of the genital system, progestogens. ATC code: G03DA04.
Pharmacology: Pharmacodynamics: Mechanism of action: Progesterone is a natural progestogen, the main hormone of the corpus luteum and the placenta. It acts on the endometrium by converting the proliferating phase to the secretory phase. GynProgest Vaginal 200 mg Capsules have all the properties of endogenous progesterone with induction of a full secretory endometrium and in particular gestagenic, antiestrogenic, slightly anti-androgenic and antialdosterone effects.
Pharmacokinetics: Absorption: Following oral administration, micronized progesterone is absorbed by the digestive tract. Pharmacokinetic studies conducted in healthy volunteers have shown that after oral administration of two 100 mg capsules (200 mg), plasma progesterone levels increased to reach the Cmax of 13.8 ng/ml +/- 2.9 ng/ml in 2.2 +/-1.4 hours. The elimination half-life observed was 16.8 +/-2.3 hours.
Although there were inter-individual variations, the individual pharmacokinetic characteristics were maintained over several months, indicating predictable responses to the drug.
Following vaginal administration, micronized progesterone is absorbed rapidly and achieves stable plasma levels in the range of 4-12 ng/ml, depending on the daily dose, with much less inter-subject variation than following oral administration.
Distribution: Progesterone is approximately 96%-99% bound to serum proteins, primarily to serum albumin (50%-54%) and transcortin (43%-48%).
Elimination: Urinary elimination is observed for 95% in the form of glycuroconjugated metabolites, mainly 3 α, 5 β-pregnanediol (pregnandiol).
Biotransformation: Progesterone is metabolized primarily by the liver.
Following oral administration, the main plasma metabolites are 20 α hydroxy-Δ 4 α-prenolone and 5 α-dihydroprogesterone. Some progesterone metabolites are excreted in the bile and these may be deconjugated and further metabolised in the gut via reduction, dihydroxylation and epimerisation. The main plasma and urinary metabolites are similar to those found during the physiological secretion of the corpus luteum.
Following vaginal administration, only low plasma levels of pregnanolone and 5 α-dehydroprogesterone are detected, due to the lack of first-pass metabolism.
Toxicology: Preclinical safety data: Preclinical data revealed no special hazard for humans based on conventional studies of safety pharmacology and toxicity.