Validating AIM-Based Instrumentation and Associated Measurement Techniques - Good Cascade Impactor Practices, AIM and EDA for Orally Inhaled Products - page 286

Fig. 10.7 Comparative 5-actuations per measurement data for the T-FSA, C-FSA, and ACI with
Qvar™-80 ( From [ 20 ]— used with permission )

for almost all practical purposes, either of these abbreviated systems could be used
for this particular formulation. However, care would need to be taken to reevaluate
the situation for formulations containing higher levels of low-volatile cosolvent.

10.4 The IPAC-RS Impactor Precision Comparison:

Comparing the Performance of an AIM ACI-Based
System Configured for pHRT Studies with a Similar
System Tailored to QC Applications

One of the central issues for AIM implementation is setting the boundary value(s)
for size-related metrics appropriately given the limited number of size fractions
produced by abbreviated systems. To a large extent, in the OIP QC environment, this
decision will likely be taken on a product-by-product basis, depending upon the product
APSD obtained in early development (see Chap. 6 ) .
Outside of the product QC environment, an alternative strategy is to set boundar-
ies to reflect areas of potential clinical interest—the sub-5 m fraction being an

obvious target for FPF , being the size limit defined for the fine particle dose in the
European Pharmacopoeia [ 4 ]. The stage cut-off diameter of stage 2 of the full-
resolution Andersen CI instrument is slightly finer at 4.7

μ

m aerodynamic diameter
at 28.3 L/min, and as a result, this size is often used as the limiting value for conve-
nience during the assessment of pMDIs. In addition to the differentiation between

μ