Quantification of Doxorubicin in Pegylated Polymer Micelles in Rat Plasma by Methanol Precipitation–Ultrasonic Emulsion Breaking Method and UPLC–MS–MS

This study established a new methanol precipitation–ultrasonic emulsion breaking method for extraction of doxorubicin from polymeric micelles and developed a UPLC–MS/MS method for the determination of doxorubicin in rat plasma. The emulsion breaking efficiency of methanol is up to 99.2%. The plasma samples were analyzed by UPLC/MS/MS using positive electrospray ionization mode in the multiple-reaction monitoring (MRM) mode. The calibration curves were linear over the range 5–1,000 ng mL −1 with the lower limit of quantification of 5 ng mL −1 . The intra- and inter-day precisions of QC samples were all <10.0%. The chromatographic separation was 2.5 min. The developed method was successfully applied to a pharmacokinetic study of doxorubicin in rats following intravenous administration.