The AIM and EDA Concepts: Why They Are Needed and How They Fit Together - Good Cascade Impactor Practices, AIM and EDA for Orally Inhaled Products - page 123

Table 5.1 Advantages of AIM and EDA approaches
AIM EDA with AIM EDA with full-resolution CI

Simpler apparatus Similar sensitivity to

APSD changes compared
to current methods

Complete APSD—useful
in diagnosis in event of
OOS/OOT with AIM
system

Fewer samples for assay More sensitive measures of

APSD shifts than with stage
groupings from full-resolu-
tion CI

Greater mass of API per
sample than with single
stages in full-resolution CI,
therefore improved
sensitivity per inhaler
actuation

Potential for fewer false-positive
results in batch release

Less recovery solvent volume
( Green Chemistry compatible)
Less time to make
measurement

Less time per measurement in
data processing with potential
for more powerful experi-
ment designs improving
coverage of the batch

potential candidate formulations. Chapter 10 contains examples of many such
studies. The general observation is that AIM-based measurements can be success-
fully made, provided that certain precautions, described in detail in Chap. 10 , are
taken. The ability to make more rapid measurements is a distinct advantage, even
though such preliminary work needs later to be supported by full-resolution CI data
for candidate products that pass the screening process.

5.5 AIM Applied in Research and Development as a Tool

for Rapid Assessment of Likely Particle Deposition
Behavior in the HRT

In the research and development environment, where the focus of attention is shifted
towards predicting the likely clinical response related to particle deposition behavior
in the lungs, the process of measurement is still simplifi ed with respect to that associ-
ated with the full-resolution CI, but an additional stage is added to enable the propor-
tion of extra-fi ne particles <ca. 1

m aerodynamic diameter to be determined (Fig. 5.6 ).
In Fig. 5.6 , the quantity IM refers to the impactor-collected mass, which differs
slightly from ISM , in that the mass on the fi rst stage of the CI is included, even if its
upper size limit is undefi ned, since the purpose here is to quantify the total mass of
API that penetrated beyond the induction port that serves to model the oropharynx.
Terms Ex-ACT and Ex-MVM refer to the total mass of API ex actuator mouthpiece

µ