Validating AIM-Based Instrumentation and Associated Measurement Techniques - Good Cascade Impactor Practices, AIM and EDA for Orally Inhaled Products - page 319

Fig. 10.43 Pressure drop-elapsed time profiles for FSI, FSI with enhanced internal volume and
NGI for DPI Product 1 determined by Pantelides et al. at a nominal flow rate of 60 L/min ( From
[ 45 ]— courtesy of D. Russell-Graham )

Fig. 10.44 Correlation between FPM <5.0μm and air acceleration rate for FSI alone, FSI with
enhanced internal volume and NGI for DPI Product 1 determined by Pantelides et al. at a nominal
flow rate of 60 L/min ( From [ 45 ]— courtesy of D. Russell-Graham )

FSI, and NGI, demonstrating that it is necessary to match internal dead space for the
abbreviated CI as closely as practical with that for the corresponding full-resolution
impactor for the most accurate work. However, at this early stage in the application
of the FSI to the measurement of aerosols from DPIs, it is possible that the effects
observed by Pantelides et al . may be DPI type specific. It follows that the addition of
dead volume may only be necessary in certain cases following a suitable comparison
to a full-resolution impactor.
The basic FSI configuration with 5

m aerodynamic diameter cut-off between
coarse and fine particle fractions has been used by Daniels and Hamilton as part of

μ