Development of chitosan-based nanoparticles for pulmonary delivery of itraconazole as dry powder formulation

The aim of current study was to illustrate a strategy to encapsulate itraconazole into chitosan-based nanoparticles using a modified ionic gelation method and to fabricate them as inhalable microparticles using spray drying technique. Different ratios of chitosan:tripolyphosphate (TPP) were prepared at pH 1.2, using higher ratios of TPP with respect to chitosan. The highest encapsulation efficiency of itraconazole into chitosan nanoparticles was found to be about 55% at 1:3 ratio of chitosan:TPP. Increasing the amount of TPP 4 times higher than chitosan resulted in the production of large particles in micron scale. Below the ratio of 1:3, the particle sizes ranged from 190 to 240 nm. Nanoparticles were characterized for morphology by TEM images. Microparticles were prepared by co-spray drying of nanoparticles with 2.5, 10 and 20% of lactose and mannitol with or without 10% of leucine, with respect to nanoparticle weights. In vitro inhalation parameters including fine particle fraction (FPF) and emitted dose percentage (ED%) were measured by a twin stage impinger (TSI). The in vitro deposition data indicated that processing of nanoparticles with mannitol and leucine could improve the aerosolization properties of the drug significantly.