Collaborative study for the calibration of Ph. Eur. Heparin Low-Molecular-Mass for Assay Biological Reference...

European Pharmacopoeia (Ph. Eur.) monograph 0828 prescribes two in vitro assays to evaluate the biological activity of low-molecular-mass heparin products. These assess the capacity of low-molecular-mass heparins to accelerate the inhibition of factor Xa and factor IIa by antithrombin. A reference standard calibrated in International Units (IU) such as the Heparin low-molecular-mass for assay Biological Reference Preparation (BRP), is required to express results. Due to low stocks, the Biological Standardisation Programme (BSP) of the Council of Europe and the European Union launched an international collaborative study to establish a replacement batch for the current Heparin low-molecular-mass BRP (BRP10). Thirteen Official Medicines Control Laboratories and manufacturers contributed data to calibrate a candidate batch against the World Health Organization (WHO) 3rd International Standard for Heparin, low molecular weight (11/176; 3rd IS) using chromogenic assays. The overall anti-Xa and IIa activities of the candidate BRP against the 3rd IS based on the participants' calculations and on central calculation at the European Directorate for the Quality of Medicines & HealthCare (EDQM) were very close. The inter-laboratory variation for both assays was between 2.8 % and 7.5 %. The study data confirmed the assigned activities of BRP10. Based on the results of this collaborative study, in December 2019 the Ph. Eur. Commission adopted the candidate BRP as Heparin low-molecular-mass for assay BRP batch 11 with assigned anti-Xa activity of 110 IU/mL and anti-IIa activity of 37 IU/mL.