The purpose of this chapter is to detail the formulation and characterization of a magnetically-targeted drug delivery vehicle, termed nano-in-microparticles (NIMs), for pulmonary drug delivery. Currently, chemotherapeutics and antibiotics are delivered systemically and result in whole body side-effects. NIMs are formulated with superparamagnetic iron oxide nanoparticles, termed SPIONs, making these particles targetable to specific lung regions using a strong external magnet. Additionally, these particles can be formulated to contain any drug or therapeutic agent, such that a therapeutic dose can be delivered to a specific tissue location using the SPIONs-magnet interaction. Finally, these particles are in the appropriate size range for pulmonary delivery, making NIMs therapeutics feasibly inhalable.To generate these particles a solution containing lactose, SPIONs, and a microsphere dye (used as a drug surrogate) is spray-dried using a laboratory-scale spray dryer. The resulting dry powder microparticles (NIMs) can be characterized for their size and morphological properties by various techniques that are presented in this chapter.The utility of NIMs as a magnetic field-dependent targeting delivery platform in an in vivo mouse model has been demonstrated, and a protocol detailing the intratracheal delivery of NIMs dry powder is included as a separate chapter in this book.
Keywords: Dry powders; Iron oxide nanoparticles; Nano-in-microparticles; Pulmonary delivery; Spray drying.