The efficacy of magnetic albumin microspheres in the targeted delivery of an anti-cancer agent, doxorubicin hydrochloride, has been investigated in rats. Using the tail as a target organ, the animals were intra-arterially administered with either 0.12 mg/kg of free drug, or 0.04 mg/kg of microsphere entrapped drug in the presence of a 8000 Gauss magnet applied for 30 min at the target-site. In each group, the animals were sacrificed over a 48 h period and their various tissues analysed for drug concentration using HPLC. It was found that compared to the free drug, a one-third dose of microsphere entrapped drug resulted in almost eight times higher drug exposure (AUC0-infinity) at the target site. In addition, the drug delivery to all the non-target tissues, including liver and heart, was substantially reduced. The study confirms the efficacy of magnetic albumin microspheres in the targeted delivery of chemotherapeutic agents.