Collaborative study for the establishment of replacement batches for somatropin CRS batch 1.

A project was run for the establishment of replacement batches of the European Pharmacopoeia (Ph. Eur.) Somatropin Chemical Reference Substance (CRS) batch 1. Twenty two laboratories from 16 countries took part in a collaborative study aimed at demonstrating the suitability of the candidate reference preparations to serve as working references in the tests for identification by peptide mapping and capillary electrophoresis (CE); related proteins, dimers and related substances of higher molecular mass; charged variants distribution; and/or for the assay of somatropin, as performed in accordance with the specifications of the current Ph. Eur. monographs 0950 Somatropin bulk solution, 0951 Somatropin and 0952 Somatropin for injection. Further to the completion of the study the Ph. Eur. Commission adopted one candidate in March 2006 as somatropin CRS batch 2 (with an assigned content of 1.69 mg somatropin monomer per vial) and the second one in June 2006 as somatropin/desamidosomatropin resolution mixture CRS batch 1 (prescribed use of the latter standard is restricted to the test for related proteins).