Nanobubbles: A Novel Targeted Drug Delivery System

Abstract Nanobubbles are nanometer size bubbles having different constituents of varying physicochemical characteristic for the inner core and outer shell. Nanobubbles are mainly fabricated to improve the stability, bioavailability and improve the biodistribution of the delivered drug to the specific targeted site. Their small sizes bubbles allow the possibility of extravasation from blood vessels into the surrounding tissues and ultrasound-targeted site-specific release with minimal invasiveness. Nanobubbles are developing as important contrast agents for imaging and carriers for drug delivery at targeted region. Sonication is the primary method for preparation of nanobubbles followed by thin-layer evaporation, high shear emulsification, mechanical agitation and coacervation or coalescence. With exposure to ultrasound/extracorporeal shock waves, the drug is liberated from the nanobubbles into the target cells. This review paper is an effort to reveal the different formulation development techniques briefly and varying shell and core content for developing nanobubbles.

摘要：纳米气泡（Nanobubbles）是内核与外壳由理化特性各异的不同组分构成的纳米级气泡。制备纳米气泡主要旨在提升递送药物的稳定性、生物利用度，并优化其向特定靶位点的生物分布。这类微小尺寸的气泡可实现从血管向周围组织的外渗，且能够在微创条件下实现超声靶向特异性药物释放。纳米气泡正逐步发展成为重要的成像造影剂以及靶向区域药物递送载体。超声法（Sonication）是制备纳米气泡的主流方法，此外还包括薄层蒸发法、高剪切乳化法、机械搅拌法以及凝聚法与聚结法。当受到超声或体外冲击波作用时，药物会从纳米气泡中释放进入靶细胞。本综述旨在简要阐述纳米气泡的各类制剂开发技术，以及用于制备纳米气泡的多样化外壳与内核组分。