A bioequivalence study of two urinary follicle stimulating hormone preparations: Follegon and Metrodin

Abstract

The purpose of this study was to demonstrate bioequivalence between two follicle stimulating hormone (FSH)-only gonadotrophin preparations (Follegon(R) and Metrodin(R)) after a single i.m. injection of IU FSH in-vivo bioactivity. A total of 16 healthy normally cycling females were treated for 7 weeks with a high-dose oral contraceptive containing 50 microg ethinyl oestradiol plus 2.5 mg lynestrenol (Lyndiol(R)) to suppress endogenous gonadotrophin production. After 3 and 5 weeks or oral contraceptive treatment, each subject received 300 IU Follegon or Metrodin in a random order. Frequent blood sampling was performed to measure immunoreactive FSH for pharmacokinetic analysis. After normalization for the immunodose administered, Follegon and Metrodin were bioequivalent with respect to the extent and the rate of absorption, the elimination half-life and plasma clearance per kg. The time taken to reach peak plasma FSH concentrations was shorter with Follegon than with Metrodin. Because bioequivalence was proved for the major pharmacokinetic variables, it can be assumed that Follegon and Metrodin are also equally effective inovulation induction, in-vitro fertilization and embryo transfer programmes and the treatment of male infertility.