[The Somatropin Reference Standard (Control 951) of the National Institute of Health Sciences]

Somatropin material was examined for preparation of the "Somatropin Reference Standard". The candidate material was evaluated by a domestic collaborative study in which eight laboratories participated. The protein content was determined to be 4.5 mg/Vial based on amino acid analysis. Because of the possibility of application as a chemical reference standard for assay by the HPLC method, a physico-chemical evaluation of the candidate material was also performed. By SE-HPLC, the content of polymer, dimer were determined to be 0.54%, 0.98%, respectively. By RP-HPLC, the early peak area ascribed to desamido and sulfoxide form was 1.07% of the total peak area. And for informational data, the potency of the candidate material, being estimated by three different biological methods, weight gain assay, tibia test and adiposeconversion assay is 14.8 IU/vial. Based on the above results, the candidate was authorized as the Somatropin Reference Standard of the National Institute of Health Sciences.