Evaluation of drug delivery following the administration of magnetic albumin microspheres containing adriamycin to the rat

The disposition of adriamycin following its intra‐arterial administration in rats as a solution (control) or via magnetic albumin microspheres (treatment group) has been investigated. The rat tail was demarcated into three segments: T1, the pre‐target site; T2, the target site; and T3, the post‐target site. In both groups, 2.0 mg/kg of adriamycin HCl was injected into the ventral caudal artery in T1 through a T‐piece cannula. A magnetic field of 8000 G was directed towards T2. The concentration of adriamycin was measured in the heart, kidney, liver, lung, serum, small intestine, spleen, T1, T2, and T3 as a function of time using an ion‐pairing HPLC assay. Areas under the mean adriamycin concentration–time curves were used to determine two indices of drug delivery: the relative tissue exposure and targeting efficiency. It was demonstrated that the magnetically responsive albumin microspheres altered the tissue distribution of adriamycin in rats. Administration of drug via magnetic microspheres was shown to increase the relative drug exposure to both T2 and liver.