Selective destruction of contrast agent microspheres [drug delivery application]

Recent studies have shown that ultrasound contrast agent may be used to deliver drugs. These drugs are directly released to the target tissue when the microspheres are exposed to high amplitude acoustic waves. The goal of this study was to investigate the destruction of microspheres by ultrasound waves to better understand the rates of transport and release that could provide the optimal spatial and temporal pattern for a drug delivery system. Experimental investigations have demonstrated that depending on the transmitted frequency, certain microsphere sizes within the same distribution are easier to rupture than others, and therefore can be selectively destroyed. These results were confirmed by measurements performed on filtered distributions. The study illustrates the potentials of ultrasound contrast agent for pharmacological applications. Different therapeutic compounds can be loaded within microspheres of different sizes and the release can be selectively activated from different regions in the size distribution.