Quantitation of Cremophor EL in human plasma samples using a colorimetric dye-binding microassay

Anal Biochem. 1998 Jan 15;255(2):171-5. doi: 10.1006/abio.1997.2467.


This paper describes an analytical procedure for the quantitative determination of the pharmaceutical vehicle Cremophor EL in human plasma samples. The procedure is based on rapid binding of Coomassie brilliant blue G-250 to Cremophor EL following plasma protein precipitation with acetonitrile and analyte extraction with n-butylchloride. The binding of the dye to Cremophor EL causes a shift in the absorption maximum from 465 to 624 nm, which is monitored using an automated microplate-absorbance reader. The assay permits estimation of Cremophor EL concentrations in the range 0.05-1.00% (v/v) in 50 microL of human plasma, with percentage deviation and precision of < or = 12 and < or = 15%, respectively. The assay was subsequently used to measure Cremophor EL concentrations in plasma samples in support of a project to develop a pharmacokinetic model for this compound in patients receiving paclitaxel.

MeSH terms

  • Antineoplastic Agents, Phytogenic / therapeutic use
  • Calibration
  • Colorimetry / methods*
  • Coloring Agents / metabolism*
  • Female
  • Glycerol / analogs & derivatives*
  • Glycerol / blood
  • Glycerol / metabolism
  • Humans
  • Ovarian Neoplasms / blood
  • Ovarian Neoplasms / drug therapy
  • Ovarian Neoplasms / metabolism
  • Paclitaxel / therapeutic use
  • Pilot Projects
  • Reproducibility of Results
  • Rosaniline Dyes / metabolism*
  • Surface-Active Agents / metabolism*


  • Antineoplastic Agents, Phytogenic
  • Coloring Agents
  • Rosaniline Dyes
  • Surface-Active Agents
  • cremophor EL
  • coomassie Brilliant Blue
  • Paclitaxel
  • Glycerol