Robustness of iCIEF methodology for the analysis of monoclonal antibodies: an interlaboratory study.

An international team including 12 laboratories from 11 independent biopharmaceutical companies in the United States and Switzerland was formed to evaluate the precision and robustness of imaged capillary isoelectric focusing for the charge heterogeneity analysis of monoclonal antibodies. The different laboratories determined the apparent pI and the relative distribution of the charged isoforms for a representative monoclonal antibody sample using the same capillary isoelectric focusing assay. Statistical evaluation of the data was performed to determine within and between laboratory consistencies and outlying information. The apparent pI data generated for each charged variant peak showed very good precision between laboratories with RSD values of less than 0.8%. Similarly, the RSD for the therapeutic monoclonal antibody charged variants percent peak area values are less than 11% across different laboratories using different analyst, different lots of ampholytes and multiple instruments. These results validate the appropriate use of imaged capillary isoelectric focusing in the biopharmaceutical industry in support of process development and regulatory submissions of therapeutic antibodies.

Capillary electrophoresis of proteins in a quality control environment.

A method for determining the purity of recombinant carboxypeptidase B utilizing CE-SDS has been developed and validated for use in a manufacturing quality control laboratory. The method was optimized, prior to validation, to allow for the lowest limit of quantitation. The method was validated with the typical ICHQ2A parameters, including accuracy, linearity, LOQ, precision, robustness/ruggedness, and specificity. All validation parameters met the acceptance criteria defined in the validation protocol.