A sensitive liquid chromatography/electrospray tandem mass spectroscopy method for simultaneous quantification of a disulfide bond doxorubicin conjugation prodrug and activated doxorubicin: Application to cellular pharmacokinetic and catabolism studies.

•An UPLC–MS/MS method is developed for simultaneous determination disulfide-linked doxorubicin prodrug and activated doxorubicin in cancer cells.•The method provides efficient sample preparation with acetonitrile precipitation and remove of intercalated doxorubicin through bath sonication.•The method is suitable for the in vitro study of doxorubicin prodrug nanoparticles.