چکیده (انگلیسی):

The purpose of this review is to discuss the roles of cascade
impactor (CI) data in inhaler assessment and to examine the
relationship between aerodynamic particle size distribution
(APSD) and the clinical response to inhaled drugs. A systematic
literature search of studies linking APSD to clinical
response was undertaken. Two distinct roles for CI-generated
data were identified: (1) the control of inhaler/drug product
quality; and (2) the provision of data that may be predictive of
particle deposition in the respiratory tract. Method robustness
is required for the former application, combined with simplicity
in operation, resulting in rudimentary attempts to mimic
the anatomy of the respiratory tract. The latter necessitates
making the apparatus and its operation more closely resemble
patient use of the inhaler. A CI cannot perfectly simulate the
respiratory tract, since it operates at constant flow rate, while
the respiratory cycle has a varying flow-time profile. On the
basis of a review of studies linking APSD to clinical response
of inhaled drugs, it is concluded that attempts to use CIgenerated
data from quality control testing to compare products
for bioequivalence are likely to have only limited success,
as links between laboratory-measured APSD, particle deposition
in the respiratory tract, and clinical response are not
straightforward.