The triblock copolymer, Pluronic P105, has been found to be an ideal ultrasonically activated drug delivery vehicle because it forms micelles with hydrophobic polypropylene oxide cores that sequester hydrophobic drugs (Fig. 1). These micelles release their contents upon the application of low frequency ultrasound such that drugs can be released specifically at the ultrasonicated region (Fig. 2). Such ultrasonically controlled release has been effective against cancer cells in vitro  and in vivo .
The purpose of this research is to assess the use of these novel polymeric micelles in ultrasonically-activated Doxorubicin® (DOX) delivery to tumors. This cancer therapy involves the exposure of the animal to localized ultrasound. Currently, one of the most effective therapies for cancer treatment involves the use of chemotherapeutic agents such as DOX. One of the major drawbacks of this therapy is that the drug attacks allrapidly dividing cells, causing healthy tissues to die. These localized treatment using micelles and ultrasound may alleviate the negative side effects of the drug on healthy tissues. Encapsulation prevents drug interaction with cells. Localized release of DOX by ultrasound limits the areas within the patient where the drug can take effect. While cell viability studies have been performed using this delivery system , no research has been performed in vivo to measure the pharmacokinetics of DOX using ultrasonic-drug delivery with micelles. This project’s goal is to quantitatively measure the drug concentration profile with time in various rat tissues, including induced tumors; to determine the concentration-time difference (if any) between ultrasonicated and non-ultrasonicated tumors; and to determine if there is drug accumulation in the studied tissues.