Low-temperature manufacturing of fine pharmaceutical powders with supercritical fluid aerosolization in a Bubble Dryer (R)

Aerosols play an important role in thin film deposition, fine powder genera tion, and drug delivery. Green processes to form aerosols are needed to eli minate the use of toxic organic solvents and minimize the production of liq uid wastes and the emission of halogenated and oxidant-forming organic comp ounds. We have developed a new patented process, Carbon Dioxide-Assisted Ne bulization with a Bubble Dryer(R) (CAN-BD), that can generate a dense aeros ol with small droplet and microbubble sizes that are dried to form particle s less than 3 mum in diameter [1-9]. The process uses carbon dioxide as an aerosolization aid, and this permits drying at lower temperature than usual ly needed in conventional spray-drying. Intimate mixing of supercritical ca rbon dioxide with aqueous protein solutions causes the formation of microbu bbles, which are rapidly dried in less than 5 s. The process is more enviro nmentally benign than traditionally used methods, and is superior when ther mally unstable materials are being processed. Fine-particle pharmaceutical powders can be rapidly and easily made by this new CAN-BD process, requirin g less energy and eliminating residues of toxicologically or environmentall y objectionable solvents. Manufacturing dry powders of pharmaceuticals for pulmonary drug delivery and increasing bioavailability are the purposes of developing and marketing the new Temco Bubble Dryer.