Spray drying is a very useful technique to produce inhalable dry powders with predetermined specifications. There is significant research activity in dry powder aerosol formulation to treat several diseases including asthma, tuberculosis, diabetes and bacterial infection in the lung. Spray drying offers great potential to these applications because of the easy achievement of the accepted optimum size range for locally acting inhaled drug particles (about 0.5 - 3.3 µm which represents deposition in the lung alveoli). The key benefits of this technology are the possibilities to control the size and morphology of the particles under a relatively gentle processing method. Indeed, this method has been proven for the preparation of heat-sensitive materials such as protein based drugs. While the traditional bench-top spray dryers have been shown capable tools for the laboratory aim generation of respiratory sized particles, the area of process technology is ever-evolving. The Nano Spray Dryer B-90 offers new possibilities in the field of laboratory scale spray drying and eliminates some weak points of traditional spray dryers; including increased recovery (up to 90%), small quantity production (100 mg amounts) and highly definable particle size ranges (300 nm - 5 µm).
Laboratory scale spray drying of inhalable drugs: A review