Target organ disposition and plasma pharmacokinetics of doxorubicin incorporated into albumin microspheres after intrarenal arterial administration.

We synthesized doxorubicin (Adriamycin, Adria Laboratories, Columbus, OH)-loaded human albumin microspheres (containing approximately 1% doxorubicin w/w) between 15 and 20 micron in diameter. Intrarenal arterial administration of 99mTC-labeled microspheres demonstrated a high renal entrapment ratio (97% of recovered radioactivity). The pharmacokinetics and metabolism of doxorubicin are different when it is administered in microspherical form. Peak plasma levels are lower (16 ng/ml versus 135 ng/ml) compared with treatment by a doxorubicin solution. Histologic studies showed that the microspheres were trapped within capillaries and small arterioles in the renal vascular arcade. It is apparent that chemoembolization with doxorubicin-loaded microspheres significantly reduces systemic exposure to the antineoplastic agent, and maintains intrarenal drug levels.