Particle formation and capture during spray drying of inhalable particles.
An investigation of the spray drying process is made in great detail regarding particle formation and capture efficiency with focus on the production of inhalable particles. Mannitol was spray dried as model substance and the spray-dried products were characterized. The resulting products consisted of smooth spheres with a volume median diameter of 2.2-5.5 microm, and narrow size distributions. The investigation was performed in pilot scale of sufficient size to draw general conclusions and make some recommendations. It has been shown that the size of particles is decreased when the feed concentration is decreased, the nozzle gas/feed flow mass ratio increased, and the droplet size decreased. The collection efficiency of the cyclone device used in this study was shown to have a cut-off of 2 microm, i.e., 50% of the particles less than 2 microm are not captured. The data reported indicate that the majority of the single particles formed here, <5 microm, arise from single droplets (of about 10 microm) and are solid, nonporous particles.
Mosén
Kristina
K
Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, Copenhagen, Denmark.
Bäckström
Kjell
K
Thalberg
Kyrre
K
Schaefer
Torben
T
Kristensen
Henning G
HG
Axelsson
Anders
A
D000280:Administration, Inhalation; D000336:Aerosols; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002627:Chemistry, Physical / Q000379:methods; D004339:Drug Compounding / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D004353:Drug Evaluation, Preclinical / Q000379:methods; D008353:Mannitol / Q000737:chemistry; D010316:Particle Size; D011208:Powders; D013548:Sweden
D000336:Aerosols; D011208:Powders; D008353:Mannitol