Endocrinology: Variability in the immunoreactive and bioactive follicle stimulating hormone content of human urinary menopausal gonadotrophin preparations

The within- and between-batch variation in the immuno-reactive and in-vitro bioactive FSH content of Pergonal, Metrodin and Metrodin-HP was investigated. Three batches of Pergonal and Metrodin, consisting of three ampoules in each batch, and three batches of Metrodin-HP, consisting of between one and three ampoules per batch, were selected at random. The follicle stimulating hormone (FSH) content of Pergonal, Metrodin and Metrodin-HP was determined by radioimmunoassay (R-FSH) and the in-vitro rat Sertoli cell bioassay (B-FSH) using the international urinary standard 70/45. The variability in the FSH content of the preparations was evaluated within and between batches by analysis of variance. Within-batch variability of B-FSH was not observed in Pergonal or Metrodin-HP but was seen in two batches of Metrodin in which the potency varied by up to 2.4 fold (P = 0.03). The between-batch R-FSH potencies of Pergonal (P1–P3) varied, with P2 (59.8 ± 0.6) and P3 (61.7 ± 0.9) being higher than P1 (47.1 ± 1.5 mean ± SEM IU/ampoule, P < 0.01). A similar pattern of variability was observed for B-FSH. For Metrodin, each of the batch R-FSH potencies was dissimilar (P < 0.02), with estimates ranging from 34.9 ± 1.2 to 64.3 ± 1.8 IU/ampoule. Furthermore, the extensive within-batch B-FSH variation from two batches confounded any meaningful comparison of between-batch variability. For Metrodin-HP, there was no between-batch B-FSH variation (29.0 ± 6.1 to 33.0 ± 0.3 IU/ampoule) and the R-FSH content was also well controlled (41.2 ± 0.5 to 46.9 ± 1.1 IU/ampoule). The B: I(bioassay: immunoassay) FSH ratios of Pergonal (0.9 ± 0.1, n = 9), Metrodin (2.2 ± 0.3, n = 9) and Metrodin-HP (0.7 ± 0.04, n = 5) were all dissimilar (P < 0.03). Within- and between-batch variations were observed to varying degrees in three human urinary gonadotrophin preparations. The variations in B-FSH content between the preparations appeared more extensive than for R-FSH. Of the preparations studied, Metrodin-HP exhibited the least variability.