Abstract
Pulmonary drug administration has many advantages over other delivery routes in both local and systemic drug delivery, since the lungs have a large surface area, thin absorption barrier and low enzymatic metabolic activity. We have reported several methods to design and prepare the submicron-sized particles suitable for nebulization or dry powder inhalation. Elcatonin loaded surface-modified DL-lactide/glycolide copolymer (PLGA) nanospheres coated with chitosan (CS) were prepared by the emulsion solvent diffusion method for pulmonary delivery of peptide. The resultant CS-modified PLGA nanospheres were confirmed to improve the pulmonary delivery of peptide with a nebulization system. With respect to the dry powder inhalation, nanoparticles of drugs could be obtained by a novel supercritical carbon dioxide method with a combination of supercritical antisolvent precipitation and rapid expansion from supercritical to aqueous solution. The resulting particles showed superior inhalation properties in an in vitro inhalation test using the cascade impactor. Nanotechnology focusing at particle design to control the particle size and surface properties may be a promising tool for developing effective pulmonary delivery systems.
