Process optimisation
PAT tools and process optimisation

Comprehensive process monitoring is necessary in the development and subsequent production of high-value products, particularly in the biotech and pharmaceutical sectors, for internal quality assurance and regulatory compliance documentation.

Process analytical technologies, which include everything from product temperature sensors to online mass spectrometers, provide insight into complex processes and enable stable drying processes.

As a technology leader, we provide the following tools for our customers:

01.LyoCam 2.0 – Camera system
02.WTMplus 2.0 – Wireless product temperature measurement
03.RFID reader
04.LyoCoN – Controlled nucleation
05.MTMplus – Manometric temperature measurement
06.Capacitive sensor in addition to Pirani-gauge
07.LyoBalance – Microbalance
08.LPCplus – Process visualization

Industrial-scale freeze-drying requires robust processes that are initially developed on pilot systems and then scaled up. The objective is to develop drying recipes (profiles of vacuum and shelf temperature versus time) that allow the best possible quality to be achieved in the shortest possible time.

Pilot systems must therefore have the same technology and geometry as the subsequent production freeze-dryer, such as rectangular product chambers and shelves, cooled and heated by liquid media.

The following table lists the parameters used by Christ for process control and monitoring. When used together with basic recipes stored in the freeze dryer control system for various products, an automatic, self-optimising process can be achieved.

Feature
Function
Area of application
WTMplus 2.0 T-sensor wireless
Product temperature measurement, wireless
Process monitoring, determination of completion of drying
T-sensor wired
Product temperature measurement, traditional wired
Process monitoring, determination of completion of drying
Lyo-Rx
Measurement of electrical resistance shows freezing-/melting point
Determination of freezing point,
self-optimising sharp cycle possible
p (Pirani)
Drying vacuum, dependent on gas type
Display of drying vacuum
p (capacitive)
Drying vacuum (independent of gas type)
dp/dt
Drying vacuum (independent of gas type)
Measurement of pressure increase in product chamber by closed intermediate valve
If the value falls below an adjustable limit value, the end of the main drying process is reached; can be used for automatic switching to the secondary drying process.
dp/dt, manometric pressure measurement (MTM)
By measurement with rapid-closing intermediate valves, determination of T at the sublimation interface, and further thermodynamic characteristics
Understanding the process, avoiding collapse
Comparative pressure measurement
Indicator to determine the end of drying of the main drying process
Process monitoring
Controlled nucleation
Uniform freezing for homogenous drying and product properties
Ice fog + over-pressure method
LyoCam 2.0
Visual
Drying quality, artefacts, faults
Scale
Measurement of product weight during drying
End of drying, sublimation speed, can be used for further switching to post drying
Annealing
Also referred to as tempering (crystal growth by moderate heating of the frozen product)
More rapid drying without collapse,improved structure
dTfreezing
Lowest product temperature before switching over to Freezing -> Main Drying
Reliable freezing,
No defrosting or collapse of the product in entry to main drying
dTmain drying
Lowest product temperature before switching over to the next process stage
Reliable drying (main drying and final drying)
Ice condenser temperature
Display and check whether desublimation is possible
Onset while large amounts of steam are present and stabilisation indicates completion of drying
Tshelf ON / OFF
Heating fluid temperature in shelf, flow and return
Difference indicates energy consumption due to sublimation
psafety
Pre-selectable safety pressure
Product protection, Sharp cycle, limited by psafety
pAlarm
Pre-selectable alarm pressure
Product protection,Sharp cycle, limited by palarm
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