Collaborative Study for the Establishment of National Reference Standard for Molecular Size Distribution Test of Human Immunoglobulin Products

Human immunoglobulin is a plasma-derived medicinal product that is the second-largest product in the number of the national lot release in the National Institute of Food and Drug Safety Evaluation (NIFDS), following human serum albumin. Reference standards are used to confirm the validity of each national lot release test. This study aims to establish a national reference standard (NRS) for the molecular size distribution test applied to immunoglobulin based biologics. 7200 vials, containing 2 mL/vial, were prepared according to the approved manufacturing process for human immunoglobulin intended for intramuscular administration. Four laboratories, including the NIFDS, and manufacturers of human immunoglobulin products, participated in this collaborative study, in which a molecular size distribution test was performed on candidate vials using size-exclusion high-performance liquid chromatography. Retention of dimer relative to monomer was 0.851. Relative to a human immunoglobulin (molecular size) biological reference preparation, relative retention times of monomer and dimer from the candidate vial were 1.001 and 1.000, respectively. This result satisfies the requirements of monographs in the European Pharmacopoeia. Based on a real-time stability evaluation over 24 months following manufacture, and a short-term stability evaluation over 14 days after opening, the dimer to monomer relative retention ratios were found to be distributed within control limits, thereby validating stability. The results of this study support registration of this candidate with the NIFDS as the NRS for molecular size distribution test of human immunoglobulin products.