ABSTRACT
The realization that blood sugar levels must be kept in normal limits if diabetic complications are to be avoided has led to the approach of self-regulated insulin delivery systems. Cavitation is one of several possible mechanisms through which ultrasound can interact with liquid medium. Acoustic cavitation can be considered to involve at least three discrete stages: nucleation, bubble growth and, under proper conditions, implosive collapse. The enhanced release was also observed in nonerodible systems exposed to ultrasound for which the release is diffusion-dependent. In vivo studies on a model drug have suggested the feasibility of ultrasound-mediated drug-release enhancement. The results suggest the feasibility of ultrasound to enhance the release of peptides and proteins from bioerodible and nonerodible polymers. Nucleation of bubbles occurs at weak points in the liquid, such as gas-filled crevices in suspended particulate matter, or from transient microbubbles from prior cavitation events.
