Malvern Instruments Spraytec, User Manual

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the range. This allows for fluctuations in the spray concentration during the
measurement. It is enabled by default.
'
N o t e
. Disabling Concentration-weighted average causes the average to be
calculated based on the assumption that each record is equally important
in determining the final result. Only do this if the spray concentration
does not change significantly across the range of records selected.
.
Keep the Average scatter data button selected, select the Phase average
check box and click its Configure button to open this dialogue:
.
Phase averaging is generally used with single shot spray systems such as
nasal sprays. It produces the averages of the start (formation), middle (fully
developed) and end (dissipation) phases of a single event. The averages
produced are stored as .
psd files.
The phase average is defined as follows:
Start phase – from the first measurement recorded as part of an event
(Time = 0 sec) until the specified time T1. This phase is termed the
formation phase by the FDA guidance for nasal spray characterisation.
Middle phase – from time T1 until time T2. This is generally set to
include the region of the spray event where the particle size is relatively
stable. This phase is termed the
fully developed phase by the FDA guidance.
C H A P T E R 5
S p r a y t e c
P a g e 5 . 2 1