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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