Biomedical Engineering Reference
In-Depth Information
100
NGI
FSI
80
60
40
20
0
FPM
<5.0µm
TEM
Fig. 10.55
Comparison of MDI formulation using NGI and FSI reported by Sheng et al
.
based on
FPM
<5.0μm
and
TEM
; error bars represent ±1 SD (
From
[
50
]—
used with permission
)
proprietary budesonide HFA suspension pMDI formulations were measured at a
flow rate of 30 L/min, using the FSI, also with 5
m cut-off for
FPM
, using the NGI
as the reference apparatus. The results (Fig.
10.55
—one product) were compared in
terms of fine particle dose (
FPM
<5.0μm
) and total emitted mass (
TEM
) using a two-
side
t
-test on the basis of the null hypothesis
FPM
5.0μm-NGI
=
FPM
5.0μm-FSI
and
TEM
NGI
=
TEM
FSI
. No statistical difference was observable between these two sets of
data (
p
> 0.05).
In the second part of their investigation, four proprietary budesonide liquid sus-
pension formulations (A, B, C, and D) containing particles of different morpholo-
gies and concentrations were nebulized with an Aeroneb Go
®
(Aerogen Ltd.,
Ireland) vibrating membrane system (
n
= 3 replicates at each condition). The aerosol
passed through an Aeroneb Go
®
/NGI induction port mouthpiece adaptor prior to
reaching the impactor.
A flow rate of 15 L/min has been recommended for nebulizer testing [
51
].
However, since at that time, there was no commercially available option to operate
the FSI at flow rates <30 L/min (
but see method adopted by Tservistas et al.
[
52
]
later in this section
), Sheng et al. operated their FSI at this lower limit in this inves-
tigation. The FSI yielded similar results for
FPM
<5.0μm
and
TEM
to those of NGI for
all formulations (Fig.
10.56
). Importantly, the values of
TEM
encompassed a wide
dosage range of ca. 80
μ
g, but as with the pMDI-aerosol measurements, the differ-
ence between the two measurement techniques for each formulation was not statis-
tically significant for each formulation (
p
> 0.05).
In 2010, Sheng and Watanabe extended the original work to evaluate the FSI as a
tool for the rapid screening of pMDI-based formulations in early-stage OIP develop-
ment [
53
]. They confirmed agreement (
p
> 0.05) between measures of
FPM
<5.0μm
deter-
mined by both FSI and NGI during the screening of pMDI formulations (Fig.
10.57
).
μ
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