Particle Size of Inhalation Aerosol Systems I: Production of Homogenous Dispersions

Abstract

The methods used to size inhalation aerosol a and the problems involved in producing an homogenous cloud of aerosol particlea are reviewed. Particle size analyses were carried out using a Royco 225/508 particle size analyser. A number of variables such as sensor head position have been examined under conditions of constant temperature and humidity. It is shows that a dilution of the aerosol cloud into a large volume (360 1) gives a satisfactory number of particles in the sample volume. The positioning of the sensor head is not critical provided that adequate air turbulence can be generated using sleeved sintered-bearing fans. The air flow rate sust be controlled so that air passes over the sensor at not anre than 0.58 m.s⁻¹. The length of time required to produce a uniform diatribution is shown to be about 10 secs.