Bioequivalence of Genotropin and Somatonorm

The bioequivalence parameters, AUC, Cmax and Tmax were calculated from serum hGH concentration-time curves after subcutaneous injections of Genotropin (recombinant somatropin) and Somatonorm (somatrem) in a two-period crossover study in 11 healthy men aged 21-35 years. Cmax was 53.4 and 62.9 mIU/litre and Tmax was 5.3 and 4.0 hours for Genotropin and Somatonorm, respectively. Criteria for bioequivalence were fulfilled for AUC. The bioavailability of Genotropin given subcutaneously was determined from the data obtained in the study above, and after an intravenous injection of Genotropin in the same dose (0.1 IU/kg body weight). The measured bioavailability of 71% could be an overestimate due to interference by endogenous hGH.