Comparison of efficacy, toxicity and pharmacokinetics of free adriamycin and adriamycin linked to oxidized dextran in rats.

Abstract
Adriamycin linked to oxidized dextran (ADM-OXD) via Schiff''s base formation was compared with free adriamycin with regard to antitumor activity, acute toxicity and plasma pharmacokinetics in rats following i.v. administration. ADM-OXD showed higher activity against Walker carcinosarcoma 256 than free adriamycin. On the other hand, the acute toxicity of ADM-OXD was about three times less than that of free adriamycin. In contrast to free adriamycin, a very high plasma level of adriamycin was found after i.v. administration of ADM-OXD. The area under the plasma concentration curve with ADM-OXD was about 160-fold higher than with free adriamycin. Thus, the improvement of the therapeutic index in the case of ADM-OXD might be due to the difference in the disposition of ADM-OXD and free adriamycin in rats.