Considerations and Some Practical Solutions to Overcome Nanoparticle Interference with LAL Assays and to Avoid Endotoxin Contamination in Nanoformulations

Methods Mol Biol. 2018;1682:23-33. doi: 10.1007/978-1-4939-7352-1_3.


Monitoring endotoxin contamination in drugs and medical devices is required to avoid pyrogenic response and septic shock in patients receiving these products. Endotoxin contamination of engineered nanomaterials and nanotechnology-based medical products represents a significant translational hurdle. Nanoparticles often interfere with an in vitro Limulus Amebocyte Lysate (LAL) assay commonly used in the pharmaceutical industry for the detection and quantification of endotoxin. Such interference challenges the preclinical development of nanotechnology-formulated drugs and medical devices containing engineered nanomaterials. Protocols for analysis of nanoparticles using LAL assays have been reported before. Here, we discuss considerations for selecting an LAL format and describe a few experimental approaches for overcoming nanoparticle interference with the LAL assays to obtain more accurate estimation of endotoxin contamination in nanotechnology-based products. The discussed approaches do not solve all types of nanoparticle interference with the LAL assays but could be used as a starting point to address the problem. This chapter also describes approaches to prevent endotoxin contamination in nanotechnology-formulated products.

Keywords: Endotoxin; Inhibition enhancement control; Interference; LAL.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cations / analysis
  • Drug Contamination
  • Endotoxins / analysis*
  • Equipment Contamination
  • Limulus Test / methods*
  • Nanoparticles / chemistry
  • Nanoparticles / microbiology*
  • Nanotechnology
  • beta-Glucans / analysis


  • Cations
  • Endotoxins
  • beta-Glucans