PHYSICOCHEMICAL STUDIES ON AEROSOL SOLUTIONS FOR DRUG DELIVERY .3. EFFECT OF RELATIVE HUMIDITY ON PARTICLE-SIZE OF INHALATION AEROSOLS

The change in size of aerosol solution particles has been investigated for various humidity conditions at 37°C. The systems studied were water, 20% v/v and 50% v/v propylene glycol in water. Particle size, as determined by cascade impactor, was dependent on relative humidity; the greater the humidity the larger the measured size. The implications of the results for quality control procedures and drug formulation are discussed. © 1978, All rights reserved.