Keywords

cavitation, drug delivery, acoustically activated

Abstract

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 [1]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 [2] and in vivo [3]. This poster presents our results showing that collapse cavitation is associated with drug release. Cavitation is generally divided into two types of behavior. Stable cavitation is the stable oscillation of a bubble without collapse, and it occurs at lower acoustic intensities (Fig. 3). Collapse cavitation occurs at higher acoustic intensity when ultrasonic pressure oscillations greatly expand and then quickly collapse a gas bubble to a fraction of its volume (Fig. 3). This creates high shear stresses and a shock wave. Collapse cavitation is evidenced by the appearance of a subharmonic at one half of the ultrasonic frequency.

Original Publication Citation

Husseini, G.H., Diaz, M.A., Christensen, D.A., Richardson, E. S., and Pitt, W.G., "The Role of Cavitation in Ultrasonic Release of Doxorubicin from Pluronic (P15) Micelles", Trans. Soc. for Biomaterials, 3, 584, Memphis, Tennessee, April 27-3, 25