SIMPLE AND SENSITIVE QUANTIFICATION OF ANTHRACYCLINES IN MOUSE ATRIAL TISSUE USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND FLUORESCENCE DETECTION

Anthracyclines are very effective against soft tissue sarcomas, with cardiotoxicity being an important side effect after repeated administration. To estimate the relative cardiotoxicity of various anthracyclines and their metabolites, we developed an isolated mouse left atrium model. To relate an effect of doxorubicin, 4'-epidoxorubicin and their four main metabolites (doxorubicinol, epidoxorubicinol and the aglycons 7-deoxydoxorubicinon and 7-deoxydoxorubicinolon) to concentrations in the tissue instead of the incubation bath, a method of quantifying the anthracyclines in small tissue samples was developed. Atria were homogenized by sonication followed by extraction of the anthracyclines with methanol. The extract was directly analyzed by high-performance liquid chromatography with fluorescence detection. Recoveries for the six compounds tested ranged from 67.5% for 4'-epidoxorubicin to 100.6% for 7-deoxydoxorubinol aglycon with coefficients of variation of 2-3% at two spiked concentrations (0.1 and 1 nmol/mg of tissue). The calibration plots were linear (r2 > 0.996) over the concentration range tested (0.05-1 nmol/mg wet weight). The limits of detection (4-10 pmol/mg of tissue) were low enough to allow the determination of the anthracyclines at all relevant tissue concentrations.