Biomedical Engineering Reference
In-Depth Information
Table 10.7
Comparison of particle distribution metrics for BDP (100
L
metered volume) using three impactor methods (
From
[
28
]—
used with permission
).
n
= 3;
mean ± SD
μ
g per actuation/50
μ
TEM
(
μ
g)
FPM
<5.0μm
(
μ
g)
EFM
<1.0μm
(
μ
g)
Method
Mean
SD
Mean
SD
Mean
SD
ACI
88.2
2.5
50.8
3.1
18.4
1.1
FSA
88.2
3.3
45.9
3.7
20.9
1.9
rFSA
85.9
3.2
46.0
0.5
21.3
1.4
p
-Value
a
0.59
0.13
0.12
a
One-way ANOVA
40
FSA
rFSA
35
30
25
20
15
10
5
0
Filter
Actuator
Stage 1
Stage 2
Induction
port
FSA stage
Fig. 10.16
Deposition profiles for BDP (100
L metered volume) within the
abbreviated impactor both with (FSA) and without (rFSA) recovery of interstage drug loss (
n
= 3;
mean ± SD for each data series) (
From
[
28
]—
used with permission
)
μ
g per actuation/50
μ
Assay for BDP was undertaken by UPLC-MS in both standard FSA and rFSA
procedures.
In addition to the abbreviated CI-based measurements, benchmark full-resolution
APSD determinations based upon two actuations of the model product were made
using the ACI with collection plates coated using 1% w/w glycerol and also equipped
with the same induction port. All measurements were undertaken at a flow rate of
28.3 L/min.
Comparison of the key metrics,
TEM
,
FPM
<5.0μm
, and
EPM
<1.0μm
, are summarized
in Table
10.7
. Note that in this work, delivered dose is equivalent to
TEM
.
No statistical difference (
p
> 0.05; ANOVA) between the reported metrics was
evident. However, both FSA methods showed a tendency to slightly underestimate
FPM
<5.0μm
and marginally overestimate
EPM
<1.0μm
, when compared to equivalent
measures derived from the benchmark ACI. This finding is consistent with that dis-
cussed earlier for pMDIs containing ethanol as low-volatile cosolvent [
20
].
Importantly, this study showed no significant differences (
p
> 0.05; ANOVA)
between either rFSA or FSA methods, despite the omission of the interstage drug
deposition in the latter (Fig.
10.16
).
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