A new targeted drug delivery method uses ultrasound to image tumours, while also releasing the drug from “nanobubbles” into the tumour.
Cancer drugs can be targeted to tumours by delivering them in packets of nanoparticles, then releasing them with ultrasound. But this approach can be difficult because it requires a way to image the tumour prior to treatment. Natalya Rapoport, Ph.D., D.Sc., of the University of Utah in Salt Lake City and colleagues describe a new method of drug delivery that may address this problem. Their study appears in the July 10 issue of the Journal of the National Cancer Institute. Nanobubbles filled with the chemotherapy drug doxorubicin were injected into mice. The bubbles accumulated in the tumours, where they combined to form larger “microbubbles.” When exposed to ultrasound, the bubbles generated echoes, which made it possible to image the tumour. The sound energy from the ultrasound popped the bubbles, releasing the drug. In mice treated with this method, the nanobubbles were more effective at blocking tumour growth than other nanoparticle delivery methods. “Microbubble formulations have been developed for combining ultrasonic tumour imaging and ultrasound-enhanced chemotherapeutic treatment,” the authors write. (Source: Journal of the National Cancer Institute : University of Utah : November 2007)