RT Journal Article SR Electronic T1 Evidence Against a Bacterial Endotoxin Masking Effect in Biologic Drug Products by Limulus Amebocyte Lysate Detection JF PDA Journal of Pharmaceutical Science and Technology JO PDA J Pharm Sci Technol FD Parenteral Drug Association (PDA) SP 472 OP 477 DO 10.5731/pdajpst.2014.00999 VO 68 IS 5 A1 Jay S. Bolden A1 Mark E. Claerbout A1 Matthew K. Miner A1 Marie A. Murphy A1 Kelly R. Smith A1 Rob E. Warburton YR 2014 UL http://journal.pda.org/content/68/5/472.abstract AB The inability to detect endotoxin using compendia methods is a potential safety concern for patients due to the lack of endotoxin removal capabilities at the fill–finish stage in typical aseptic biologic drug product manufacturing. We have successfully demonstrated endotoxin challenge study recovery methodology using mammalian cell–produced biologic drug products and drug substances in citrate, histidine, phosphate, and sodium acetate buffer formulations containing polysorbate, challenged with an endotoxin analyte, for up to 6 months of storage. Successful recovery was similarly demonstrated for a preserved, peptide-containing drug product formulation. To isolate a potential masking—or low-endotoxin recovery—source, additional studies were performed to evaluate factors including product manufacturing contact surfaces, drug product matrix with and without polysorbate, individual matrix components, protein concentration, reagent suppliers, an orthogonal test method, and storage conditions. In all cases, acceptable recoveries were observed. Bacterial endotoxin is known to be chemically stable at physiological conditions. Purified endotoxin in aqueous conditions is likely to self-aggregate or bind to surfaces. Neither the nature of, nor the storage conditions of, the studied formulation matrices were shown experimentally to render the challenge endotoxin biologically inactive. The results highlight the importance of appropriate study design in assessing the recovery of endotoxins. LAY ABSTRACT: Bacterial endotoxin is a Gram-negative bacterial cell wall component that is harmful to humans at threshold concentrations, and it is not expected to be in aseptically-produced pharmaceutical medicines. It has been suggested that endotoxin cannot be detected over time in certain biopharmaceutical drug product formulations containing citrate, phosphate, and polysorbate components via an unknown masking mechanism. We have generated and present data here that indicate that endotoxin can be recovered in a variety of matrices, and under various experimental conditions.