Highly sensitive method for the determination of adenosine by LC-MS/MS-ESI: method validation and scope of application to a pharmacokinetic/pharmacodynamic study.

A highly sensitive, rapid assay method has been developed and validated for the estimation of adenosine in rat plasma with liquid chromatography coupled to tandem mass spectrometry with electro-spray ionization in the positive-ion mode. The assay procedure involves extraction of adenosine and phenacetin (internal standard, IS) from rat plasma with a simple protein precipitation extraction process. The method was validated using rat plasma with extinguished adenosine endogenous levels.