Standardisation of the method for prekallikrein activator determination in human immunoglobulin and albumin products

Abstract

Assessment of prekallikrein content is essential for safety control of human immunoglobulin and albumin products. The inherent variability of human prekallikrein reagents and chromogenic substrates indicates the need for standardisation of the chromogenic assay, using the components of a reference standard (RS) not only for construction of calibration curves, but also for confirmation of validity, consistency, and reproducibility of results within different established ranges. The aim of the study was to improve the quality control of human plasma products in terms of prekallikrein activator content. Materials and methods: prekallikrein activator content was determined by the chromogenic assay according to the procedure described in General Monograph 1.8.2.0013.18 of the Russian Pharmacopoeia, using various prekallikrein reagents. An RS was developed in a spiking test, using human albumin solution and Hageman factor beta-fragment reagent. Shewhart control charts were prepared based on the results of determination of prekallikrein activator content in the RS control component.Results: a two-component RS for prekallikrein activator content with an assigned Hageman factor beta fragment content was developed using the spiking test. The authors substantiated the necessity of using a Russian-produced prekallikrein reagent as the RS component. The in-house reference standard IRS 42-28-445 was certified using all available human prekallikrein reagents, and the IRS 42-28-446 was certified using the prekallikrein reagent included in the kit. The certified prekallikrein activator content is: 51 IU in the batches 1 of IRS components intended for prekallikrein determination; 8.3–11.9 IU/mL in the IRS 42-28-445 control component, after reconstitution in 1.0 mL of purified water, and 5.4–6.6 IU/mL after reconstitution in 2.0 mL of purified water; and 9.1–11.1 IU/mL and 5.6–6.4 IU/mL in the IRS 42-28-446 control component after reconstitution in 1.0 mL and 2.0 mL of purified water, respectively. The IRS component intended for prekallikrein determination is designed for calibration curve construction, while the IRS control component is designed for assessing the validity of test results and preparation of control charts. The analysis of the control charts for the control component made it possible to evaluate the consistency of the analytical process. Conclusions: the components of the developed RSs in combination with Shewhart control charts allow for both determination of prekallikrein activator content, and control of the analytical process, as well as assessment of changes related to the replacement of the reagent batch. The RS control component allows for assessment of analytical process consistency and ensures the standardisation of the test procedure.