Modification of inhalable powders by pulmonary surfactant components adsorbed on droplets during spray-drying process

Abstract

Inhalation of medicinal aerosols requires the specific properties of powders to assure their de-aggregation to particles within the respirable size. In this study we evaluate the influence of additives of pulmonary surfactant (PULMS) components in lactose solution used for preparation of powders by pneumatic atomization and the consecutive spray-drying (SD). It was demonstrated that PULMS in a low concentration (0.1%) changed the morphology of powder particles and improved their aerosolization properties in comparison to spray-dried lactose obtained in similar conditions. The mass median diameter of lactose/PULMS aerosol particles released from a commercial inhaler was reduced to 6.6 μm when compared to the value of 17.2 μm for lactose. At the same time the fraction of particles smaller than 5 μm was increased to 37% (from ca. 7% for lactose). These results were attributed to PULMS adsorption on droplets generated during SD process. Moreover, the particles appeared to be very effective in reducing the dynamic surface tension after dissolution in water what indicates that PULMS components are effectively incorporated into powder particles obtained by SD. This effect not only improves properties of inhalable powder but simultaneously allows to deliver PULMS to the lungs where it can act as an absorption enhancer of inhaled medicines.