Physical Causes of APSD Changes in Aerosols from OIPs and Their Impact on CI Measurements - Good Cascade Impactor Practices, AIM and EDA for Orally Inhaled Products - page 75

presented in Chap. 5 , and case studies in which abbreviated impactors have been
used successfully with all types of OIP are contained in Chap. 10 .

3.4 Concluding Remarks

This chapter has reviewed the most likely physical causes underlying potential
shifts in APSDs of aerosols emitted from the various forms of OIP and has provided
some case studies that are indicative of how a multistage CI responds to such
changes. In conclusion, it is important to appreciate that none of the causes of the
shifts that have been described affect only a select portion of the APSD, in other
words they are not especially size-selective. Hence, there are no processes envis-
aged that would selectively make the mass that is collected on one particular stage
of a multistage CI grow, while the mass on a neighboring stage drops, without a
concomitant change in the rest of the APSD profile.

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