Ultrasound mediated sonochemical internalization (SCI): overcoming the depth limitations of light-based therapies

Focused ultrasound activation of sonosensitizers i.e. sonodynamic therapy (SDT) is an alternative to light-activated photodynamic therapy (PDT). Sonochemical internalization (SCI), is comparable to light based photochemical internalization (PCI) but without the intrinsic drawback of limited penetration depth of light in biological tissues including the skull. SCI experiments were performed both in vitro on monolayers and in vivo, in a rat breast tumor model, using the sononsensitizer AlPcS2a and the drug bleomycin (BLM). in vitro; Growth inhibition of tumor cells in monolayer was significantly greater than that seen with either BLM or SDT acting alone. Similar results were also seen in vivo, with significant reduction in breast tumor development following BLM-SCI The synergist effect of SCI, employing relatively low drug concentrations and focused ultrasound power levels, would reduce the problems of nonspecific tissue damage caused by thermal effects at high power and unwanted systemic drug side effects.