Ultrasound enhanced antitumor activity of liposomal doxorubicin in mice

Liposomal encapsulation of doxorubicin (DXR) improves tumor accumulation and reduces adverse effects. One possible strategy for further optimization of this delivery technology would be to design the liposome carrier to release its content within the tumor tissue in response to specific stimuli such as ultrasound (US). In this study, the tumor uptake properties and therapeutic efficacy of 1,2 distearoyl-sn-glycero-3-phosphatidylethanolamine-based liposomes containing DXR were investigated in nude mice bearing tumor xenografts. The liposomal DXR formulation alone showed no inhibitory effect on tumor growth. However, upon exposure to low frequency US in situ inhibition of tumor growth was demonstrated.