Critical process parameters is an abbreviation of CPPs and CQAs is critical quality attributes. In this article we will learn what are the basic differences between critical process parameters and critical quality attributes and what is the relationship between these two.
Critical process parameters are defined as those parameters of the process or any equipment which must be critically controlled and observed because they have a direct or indirect impact on the product quality.
The process variables which have an impact on CQAs are known as critical process parameters or CPPs.
The variable may be as follows,
- Temperature
- Pressure
- Time
- Speed
CQAs are critical quality attributes and these are defined as the physical, chemical, biological or microbiological properties of the product which must be maintained within the required limits to obtain the desired product quality known as quality attributes or CQAs.
Critical quality attributes are process input and CQAs are output.
If our input will be right then the resultant output will also be right.
Product quality attributes are the critical qualities of the product which are checked after completion of a step or process by physical, chemical or biological analysis.
At the in-process stage, we cannot determine the product quality attribute without testing or analysis.
Due to these limitations, we identify the critical process parameters or CPPs and define a strict range and supervision of these process parameters to obtain the required CQAs.
If we keep all critical process parameters within range our quality attributes will also be within the range.
Examples
If we take the example of the drying process used for tablet manufacturing then the LOD or loss on drying will be the CQA.
Mean after the drying process the resultant output or quality indicator is the value of LOD.If the value of LOD is within the range it indicates that our drying process was carried out as per the requirements or specification.
From the above statement, it is clear that LOD is checked after the drying process so to achieve the required LOD we will identify the critical process parameters
and will ensure that these critical process parameters are maintained within the defined limits.
Following are the critical process parameters of the FBD,
- Inlet Air Temperature
- Outlet Air Temperature
- Product Temperature
- Air Flow Rate
- Drying Time
LOD or loss on drying is the critical quality attribute because if the required LOD level will not be maintained in our product it will affect our tablet compression process and tablet quality.
Explanation
If the LOD is very high it will result in sticking and picking leading towards poor tablet quality at the compression stage and if the LOD is very low it will result in tablet capping and lamination and our product will be defective.
We validate our CPPs to build the assurance of the required LOD by maintaining the critical process parameters of the drying process within the range.
Example
Suppose our required LOD for a batch of tablets is 2 to 3% and we have validated our CPPs means we can get the required LOD if we carry out our drying process at the following parameters.
Inlet air temperature is 70°C, air flow rate is 5000 m³/hr, outlet air temperature is 55°C, product temperature of 45°C and drying time is 1 hr.
Critical adherence to the above parameters give us assurance that our required LOD will be achieved after 1 hr.
But if we don’t critically observe these critical process parameters i.e inlet air temperature is not constant and air flow volume is also not sufficient for the fluidisation then the required level of LOD will not be achieved within the recommended period of time.
Difference Between CPPs & CQA
- CPPs are the parameters of the process or equipment.
- CQAs are the attributes of the product.
- Critical parameters of the process are the input and CQA is the output.
- During manufacturing, we can control or change the CPPs but we can not change CQAs directly.
- For CPPs, no analytical testing is required but for CQAs, we perform analytical testing.
Relationship
CPPs and CQAs are directly related with each other and synchronization is required because if there is any disturbance in the critical process parameter then the resultant output means critical quality attributes will also be disturbed and will not be of the required quality.
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