Innovations at INTERPHEX Guide 2022 - 20

Figure 3. Results for 5cSt silicone oil leak detection in a pilot lyophilizer.
around time t=15 mins when the conditions of pressure
and temperature in the chamber allow for maximum
evaporation of silicone oil and then continue dropping
over time.
Similarly, several experiments were also conducted in a
large scale 40m2
shelf area Lyomax40 lyophilizer. Table 1
shows the total silicone oil used in one such experiment
and the total loss of silicone oil during the experiment.
In this freeze dryer, similar tests were performed with
total quantities of silicone oil varying from 2g to 10g. The
2g sample of silicone oil distributed over 5 petri dishes
failed to produce a detectable ion current in the mass
spectrometer. However, samples of silicone oil 4g onwards
were successfully detected as shown by the plot of Ion
Currents and PPMs vs time for different quantities of oil in
Figure 4.
Petri Dish #
1
2
3
4
5
Empty wt. (g)
5.9507
6.4214
6.071
6.6229
6.4204
In the test, all petri dishes were placed on the same shelf
in the center of the chamber. However, one test with a
quantity of 8g of silicone oil was repeated by placing the
petri dishes evenly distributed between shelves 8-15.
Thus, instead of all 20 petri dishes on one shelf, two
petri dishes per shelf were placed on ten shelves in the
same 40 m2
freeze dryer. Figure 4 (right) below shows
a comparison of the results. It can be seen that there is
not a significant difference between the results obtained
from these two tests indicating that the total quantity of
silicone oil is a much larger contributor to a successful
detection of silicone oil as opposed to the distribution of
the oil inside the chamber. Note that this procedure is for
leak detection only and results will vary from this testing
if a leak occurs during a freeze-drying process where
large quantities of water vapor and nitrogen are present
in the freeze dryer. IMA has conducted several numerical
Table 1. 2g silicone oil loaded in 5 petri dishes in a Lyomax40 freeze dryer
Initial wt. (g)
6.3575
6.823
6.4728
7.0278
6.827
Initial oil (mg)
406.8
401.6
401.8
404.9
406.6
Final wt (g)
6.0963
6.5615
6.2078
6.7701
6.5598
-261.5
-265
-257.7
-267.2
Loss (mg)
-261.2
% loss
64.2%
65.1%
66.0%
63.6%
65.7%
20 |
| Innovations at INTERPHEX 2022
Innovations at INTERPHEX Guide 2022

Table of Contents for the Digital Edition of Innovations at INTERPHEX Guide 2022
