The bioequivalence of recombinant human growth hormone (rhGH) for reconstitution, at either 24 IU or 8 mg, and three strengths of liquid formulation of rhGH (5, 10 or 15 mg per 1.5 mi, hGH) was tested in two randomized, single-blind, four-period, crossover studies in healthy subjects. The study drugs were administered by subcutaneous injection at a dose of 2.5 mg rhGH/m(2) body surface area or as a fixed dose of 5 mg rhGH. Endogenous hGH release was suppressed by a continuous somatostatin infusion. The 90% confidence intervals for the estimated mean ratios of AUC(0-24 h) and C-max (analysis of variance) between all products were within 80-125% in both studies. Also, no significant differences (P > 0.05; Wilcoxon signed rank test) were found between t(max) for the liquid formulations of rhGH. These data demonstrate that there is bioequivalence between rhGH for reconstitution and the liquid formulations of rhGH. (C) 2000 Harcourt Publishers Ltd.