Validation of computational method to predict aerodynamic diameter of particles with rough surface
Two instruments, namely the Aerosizer LD and the Particle Size Distribution Analyser (PSDA) 360, were used to measure aerodynamicdiameters of spray dried bovine serum albumin (BSA) particles with different surface corrugation (DS). The measured aerodynamicdiameters were compared with the values calculated using the theoretical model previously developed by our group. The model-calculated aerodynamicdiameters have been shown to agree with the measured values for corrugated and less cohesive BSA particles with DS varying between 2.18 and 2.41. For smoother and more cohesive BSA particles with DS of 2.06 the measured and calculated values differed by 27% (compared to the value measured by PSDA 3603) and 115% (compare to the value measured by Aerosizer). This variation resulted from the difficulty to completely disperse the more cohesive particles during measurement. Hence, the model can be used to estimate aerodynamicdiameter in situations when direct measurement fails due to unavailability of equipment, limitations or difficulty in dispersing powders into their individual particles in the aerosol.