title: Choice of method for endotoxin detection depends on nanoformulation.
abstract: OBJECTIVE
  Many nanoparticles interfere with traditional tests to quantify endotoxin. The aim of this study was to compare the performance of limulus amoebocyte lysate (LAL) formats on clinical-grade nanoformulations, to determine whether there were disparate results among formats and to test the applicability of an alternative bioassay (the macrophage activation test [MAT]) for resolving discrepancies, if observed.
  
  
  METHODS
  Clinical-grade nanoformulations were tested using turbidimetric, gel-clot and chromogenic LAL. Formulations that cause a discrepancy among LAL tests were also tested by the MAT.
  
  
  CONCLUSIONS
  The gel-clot LAL method cannot be relied upon to resolve discrepancies among LAL tests for certain nanoformulations. No one LAL format was shown to be optimal for all the tested clinical-grade nanoformulations. The tested alternative bioassay (the MAT) was useful for verifying LAL findings, but only for those nanoformulations not carrying/including cytotoxic drugs.
authors.affiliation: Nanotechnology Characterization Laboratory, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, 1050 Boyles Street, Frederick, MD 21702, USA. marina@mail.nih.gov.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Dobrovolskaia
authors.forename: Barry W
authors.initials: BW
authors.lastname: Neun
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Clogston
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Grossman
authors.forename: Scott E
authors.initials: SE
authors.lastname: McNeil
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002460:Cell Line; D002626:Chemistry, Pharmaceutical; D004731:Endotoxins / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D008033:Limulus Test / Q000379:methods; D008070:Lipopolysaccharides / Q000032:analysis / Q000737:chemistry; D008262:Macrophage Activation; D050997:Nanomedicine; D053758:Nanoparticles / Q000737:chemistry; D011749:Pyrogens / Q000032:analysis
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides; D011749:Pyrogens
keywords: endotoxin; in vitro assay; interference; limulus amoebocyte lysate; lipopolysaccharide nanoparticles; rabbit pyrogen test