| 摘要 |
The present invention relates to lipid based nanoparticles or liposomes that are sensitive to ultrasonic energy, compositions containing these particles, methods for delivering one or more active agents using the particles, and methods for preparing the particles. The nanoparticles and liposomes encapsulate active agents such as chemotoxins, genes, virus vectors, proteins, peptides, antisense oligonucleotides, carbohydrates, and stem cells. The particles contain an aqueous core, at least one active agent located within the aqueous core, and a lipid bilayer or membrane that encapsulates the active agent within the aqueous core. The lipid bilayer may comprise a primary phospholipid and a lysolipid that preferably have different acyl chain lengths, making the lipid bilayer sensitive to ultrasound. Ultrasound may be used to track the particles as they move throughout the body. When the ultrasonic energy reaches a certain pressure, the lipid bilayer will break apart, releasing the active agent.
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