November 2017


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Eric Hammang <[log in to unmask]>
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Pharmaceutical Stability Discussion Group <[log in to unmask]>
Mon, 27 Nov 2017 21:18:03 +0000
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Hello All,

It has been recommended we update the validation protocol and studies for a stability chamber that will begin being used for a cycling study.
The program has 4 phases and takes 8 hours to complete before beginning again. It holds at -3C° for 3 hours, ramp to 40C° in 1 hour, holds 40C° for 3 hours, ramp to -3C° in 1 hour, and repeat.

In review of our last study, we used 16 thermocouples placed methodically and consistently throughout a 40sq. ft. walk-in chamber and I am finding that the 1 hour ramp period for both warming or cooling (plus a 15 minute stabilization period written into the protocol) was still not enough time to get all thermocouples ±2C° of specified temperature. At the time the study was conducted it appears the results of the 16 temps may have been averaged to meet the necessary criteria. We do not average temp readings for our other constant environment stability chambers validation studies and am unable to find any reference indicating it is ok for cycling validation studies.

The data indicates that some thermocouples took a total of 45 minutes into the 3 hour holding period after the 1 hour ramp period ended for stabilization within that ±2C°.

Does anyone have experience dealing with a similar scenario? I am seeking guidance for what type of language to use that offers an appropriate defense if scrutinized.

I am unable to change the cycling program times or temperatures. Also, the controller is working as intended with the input received from the thermocouple and it is capable of ramping faster when needed. For example, it took about 33 minutes to cool from 55C° to -3C° when being checked in a manual operation mode.

In these instances the chamber is running empty. We will also be simulating an approximate load of between 60-70% of the space in separate studies.

Any help is much appreciated.

Kind regards,

Eric Hammang

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