Serum and tissue concentrations of doxorubicin after IV administration of doxorubicin or doxorubicin-DNA complex to patients with gastrointestinal cancer.

Blood and tissue concentrations of doxorubicin (DOX) were assayed after an intraoperative IV test dose of either free DOX 10 mg or its DNA complex 10 mg to patients with gastrointestinal cancer. After administration of the free drug, blood DOX levels decreased in an at least biphasic way, while DOX-DNA gave higher blood concentrations, which decreased slowly with no clear inflexion point on the concentration-time curve within the first hour. Tissue concentrations of DOX did not differ significantly after the two forms of the drug, liver being the tissue with the highest levels, followed by lymph node metastases, tumor tissue, muscle, and normal intestinal mucosa. If skeletal muscle can be used as a substitute for myocardium, lower cardiotoxicity of DOX-DNA than of DOX is not likely to be due to a difference in tissue uptake and retention between the two forms of DOX.