Determination of a deuterohemin-peptide conjugate in rat plasma by liquid chromatography-tandem mass spectrometry and application to a preclinical pharmacokinetic study.

The deuterohemin-peptide conjugate (DhHP-6) is a microperoxidase mimetic, which has demonstrated substantial benefits in vivo as a scavenger of reactive oxygen species. This paper reports the development of a sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of DhHP-6 in rat plasma using triptorelin as an internal standard (IS). 50μL plasma was used in sample preparation, and a simple protein precipitation procedure with acetonitrile was involved. Satisfactory peak shapes of analyte and IS were obtained on an Agilent HC-C18 column by using a gradient elution with 10mM ammonium acetate-0.5% formic acid (v:v) and acetonitrile, there was no significant interference impacting the determination. A calibration curve obtained from this method was linear within the concentration range 10-3000ng/mL with intra- and inter-day precisions of 4.2-6.8% and 3.2-8.9%, respectively and accuracy of -1.3% to 2.1%. The recovery was above 80% with low matrix effects. The method was successfully applied to support a preclinical pharmacokinetic study in rat.