Ovidrel Mechanism of Action

Pharmacotherapeutic Group: Gonadotropins. ATC Code: G03GA08.
Pharmacology: Pharmacodynamics: Ovidrel is a medicinal product of chorionic gonadotropin produced by recombinant DNA techniques. It shares the amino acid sequence with urinary human chorionic gonadotropin (hCG). Chorionic gonadotropin binds on the ovarian theca (and granulosa) cells to a transmembrane receptor shared with the luteinising hormone, the LH/CG receptor.
The principal pharmacodynamic activity in women is oocyte meiosis resumption, follicular rupture (ovulation), corpus luteum formation and production of progesterone and estradiol by the corpus luteum.
In women, chorionic gonadotropin acts as a surrogate LH surge that triggers ovulation.
Ovidrel is used to trigger final follicular maturation and early luteinisation after use of medicinal products for stimulation of follicular growth.
In comparative clinical trials, administration of a 250 mcg dose of Ovidrel was as effective as 5000 and 10,000 IU of urinary hCG in inducing final follicular maturation and early luteinization in assisted reproductive techniques, and as effective as 5000 IU of urinary hCG in ovulation induction.
So far, there are no signs of antibody development in humans to Ovidrel. Repeated exposure to Ovidrel was investigated in male patients only. Clinical investigation in women for the indication of assisted reproductive techniques (ART) and anovulation was limited to 1 treatment cycle.
Pharmacokinetics: Following IV administration, choriogonadotropin α is distributed to the extracellular fluid space with a distribution half-life of around 4.5 hrs. The steady-state volume of distribution and the total clearance are 6 L and 0.2 L/hr, respectively. There are no indications that choriogonadotropin α is metabolised and excreted differently than endogenous hCG.
Following SC administration, choriogonadotropin α is eliminated from the body with a terminal half-life of about 30 hrs, and the absolute bioavailability is about 40%.
A comparative study between the currently registered freeze-dried formulation and the liquid formulation showed bioequivalence between the 2 formulations.
Toxicology: Preclinical Safety Data: Preclinical safety data reveal no intrinsic toxicity of choriogonadotropin α. Studies on carcinogenic potential were not performed. This is justified, given the proteinous nature of choriogonadotropin α and the negative outcome of the genotoxicity testing. Studies on reproduction were not performed in animals.