Current Approaches to APSD Measurements of OIPs Based on Inertial Impaction - Good Cascade Impactor Practices, AIM and EDA for Orally Inhaled Products - page 43

In a survey undertaken in 2006 by EPAG in connection with CI qualification
testing, the ACI was identified as the most widely used multistage CI, with the NGI
following closely in second place [ 51 ]. The MSLI came third, but this apparatus is
not in use outside of European regulatory submissions. Other systems were seldom
used. It should be noted that the glass TI (Apparatus A of the European
Pharmacopoeia) would qualify as an abbreviated impactor method, since it size
classifies the incoming aerosol into only two subfractions with its d 50 size at 6.4 μ m

aerodynamic diameter, when operated at its design flow rate of 60 L/min.

2.7 Preseparators and Induction Ports

Some form of inlet to the CI is required to ensure that the aerosol produced by the
inhaler enters the impactor in a reproducible manner. Most OIPs are designed such
that they emit their medication in the horizontal plane and entrances to impactors
are typically oriented in the vertical downward direction. The solution to the
problem is the induction port, which also mimics to a greater or lesser extent
depending on its design, the human oropharynx. There are many designs of
induction port currently in use, with their shape and capacity reflecting differing
viewpoints on how inhaler aerosols should be sampled. Seven examples are illus-
trated in Fig. 2.16 [ 52 ]. By far the most commonly encountered is the relatively