Chemotherapy agents administered to cancer patients can exert toxic effects on healthy tissues as well as tumor sites. A more precise means of delivering cancer drugs to target areas involves the use of microbubbles as intra-vascular agents carrying low-dose pharmaceutical payloads.

These micron-sized gas-filled phospholipid-shelled spheres, already clinically approved for contrast-enhanced ultrasound imaging, were tested by an international research team as vehicles for targeted cancer drug Schematic depiction of a therapeutic microbubble. Source: Nicola Ingram et al.delivery. Microbubbles were loaded with a cancer drug and antibodies attracted to the growth hormone found in high levels in the blood vessels supplying a tumor. With the antibodies serving as a navigational aid, the microbubbles became concentrated at tumor sites in animal models. Ultrasound pulses were then administered to break up the bubbles and release the drug.

In addition to more focused targeting, the payload- and antibody-laden microbubbles remained within the circulatory system much longer than when antibodies were not present. The combination increased therapeutic agent concentrations at tumors, improving treatment efficacy and allowing for lower dosing.

Scientists from St James's University Hospital (U.K.), University of Leeds (U.K.), Mansoura University (Egypt), Medicines Discovery Catapult (U.K.), University of Manchester (U.K.) and University of Bradford (U.K.) contributed to this research, which is published in Theranostics.