Caffeine in plasma and saliva by a radioimmunoassay procedure.

Journal Article (Journal Article)

Caffeine was analyzed in human plasma and saliva by a simple, rapid, and sensitive radioimmunoassay procedure. Immunization of rabbits with an antigen prepared by coupling 7-(5-carboxypentyl)-1,3-dimethylxanthine to bovine serum albumin resulted in the formation of antibodies selective for caffeine as opposed to various mono- and dimethylxanthines, mono-, di-, and trimethyluric acids and a variety of common drugs. The radioligand used for competitive binding studies was 7-(2,3-3H2-propyl)-1,3-dimethylxanthine. The procedure permits direct analysis of caffeine in plasma or saliva without extraction. Comparison with a high pressure liquid chromatography method for the analysis of caffeine gave satisfactory results and showed no evidence for interference by metabolites. A caffeine half-life of 4.0 hours determined by the radioimmunoassay was in agreement with previous work. Comparison of human plasma and saliva levels by the radioimmunoassay procedure indicated approximately equal concentrations in the two fluids.

Full Text

Duke Authors

Cited Authors

  • Cook, CE; Tallent, CR; Amerson, EW; Myers, MW; Kepler, JA; Taylor, GF; Christensen, HD

Published Date

  • December 1, 1976

Published In

Volume / Issue

  • 199 / 3

Start / End Page

  • 679 - 686

PubMed ID

  • 1033273

International Standard Serial Number (ISSN)

  • 0022-3565


  • eng

Conference Location

  • United States