Protropin has 192 amino acid residues and a molecular weight of about 22,000 daltons. Protropin is synthesized in a special laboratory strain of E. coli bacteria which has been modified by the addition of the gene for human growth hormone production. Protropin is a highly purified preparation.
Biological potency is determined using a cell proliferation bioassay.
Phosphoric acid may be used for pH adjustment. Bacteriostatic Water for Injection, USP, is a sterile water containing 0.9 percent benzyl alcohol per mL as an antimicrobial preservative packaged in a multi-dose vial. In vitro and in vivo preclinical and clinical testing have demonstrated that Protropin is therapeutically equivalent to pituitary-derived human growth hormone. Protropin stimulates skeletal growth in children with growth failure due to a lack of adequate secretion of endogenous growth hormone. Skeletal growth is accomplished at the epiphyseal plates at the ends of a growing bone.