Drug-loaded nanobubbles for ultrasound-mediated antitumor treatment

Polylactic acid (PLA) bubbles that can act both as ultrasound contrast agents and drug carriers have the disadvantage of low encapsulation efficiency and do not allow effective extravasation into the tumor tissue. In this regard, PLA and lecithin are considered drug carriers. The present study used a modified ultrasonic double emulsion-solvent evaporation technology in order to prepare paclitaxel-loaded PLA-lecithin nanobubbles. X-ray diffraction analysis (XRD) was used to investigate the state of the drug in the bubbles, whereas the tumor weight and the inhibition rate of tumor bearing mice in the ultrasound-mediated function were further examined. The results indicated that the nanobubbles prepared with a mass ratio of PLA and lecithin at 50:250 were characterized as inner hollow. The size of these particles was approximately 615 nm, and the drug loading and encapsulation reached 8.34±0.67% and 91.42±5.48%, respectively. Paclitaxel was distributed in the shell of the bubbles in an amorphous state, and the in vitro drug release was characterized by sustained release, zero release and ultrasound mediated drug release. The injection of H22 hematoma-bearing mice with ultrasound-mediated drug-loaded PLA-lecithin nano-scaled bubbles could reduce the toxicity and increase the antitumor efficacy compared with paclitaxel.