LC–MS/MS method development for quantification of doxorubicin and its metabolite 13‐hydroxy doxorubicin in mice biological matrices: Application to a pharmaco‐delivery study

This study describes the development of simple, rapid and sensitive liquid chromatography tandem mass spectrometry method for the simultaneous analysis of doxorubicin and its major metabolite, doxorubicinol, in mouse plasma, urine and tissues. The calibration curves were linear over the range 5-250 ng/mL for doxorubicin and 1.25-25 ng/mL for doxorubicinol in plasma and tumor, over the range 25-500 ng/mL for doxorubicin and 1.25-25 ng/mL for doxorubicinol in liver and kidney, and over the range 25-1000 ng/mL for doxorubicin and doxorubicinol in urine. The study was validated, using quality control samples prepared in all different matrices, for accuracy, precision, linearity, selectivity, lower limit of quantification and recovery in accordance with the US Food & Drug Administration guidelines. The method was successfully applied in determining the pharmaco-distribution of doxorubicin and doxorubicinol after intravenously administration in tumor-bearing mice of drug, free or nano-formulated in ferritin nanoparticles or in liposomes. Obtained results demonstrate an effective different distribution and doxorubicin protection against metabolism linked to nano-formulation. This method, thanks to its validation in plasma and urine, could be a powerful tool for pharmaceutical research and therapeutic drug monitoring, which is a clinical approach currently used in the optimization of oncologic treatments.