Quantitative endotoxin assay

The observation of gel formation in a test tube as an endpoint for an endotoxin assay provides the means for a very simple test. The need for more objective quantitative methods has led scientists to develop a variety of automated methods for endotoxin measurement. This discussion is limited to the three methods that were accepted by the Food and Drug Administration (FDA). 

Lipopolysaccharides (LPS) or endotoxin may be introduced as the result of low level bacterial contamination of the cell culture or during the fill of the final drug product, and can be assessed by the Limulus amebocyte lysate (LAL) assay. Similarly, antifoaming agents that are introduced during cell culture are removed during purification, but verification of removal through quantitative HPLC assays is required. Lastly, purification process impurities such as debris from resin or... 

Remillard J.F., Case Gould M., Roslansky PF. and Novitsky T.J. (1987) Quantitation of endotoxin in products using the LAL kinetic turbidimetric assay. In Detection of bacterial endotoxins with the Limuius amebocyte lysate test. Alan R. Liss, Inc, New York. 197-210. 

Teller J.D. and Key K.M. (1979) A turbidimetric LAL assay for the quantitative determination of Gram negative bacterial endotoxins. In Biomedical applications of the horseshoe crab. Alan R. Liss, Inc., New York, 423-433. 

Keller, T., and Nowotny, A., 1986, Metachromatic assay for the quantitative determination of bacterial endotoxins, Biochem. 156 189-193. 

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