System Suitability
System suitability testing (SST) is an important part of analytical method validation. It is used to verify that the analytical system is performing as expected and that the results of the analysis will be accurate and reliable.
System suitability parameter has to be selected based on tailing factor, plate count, sensitivity, resolution and RSD.
In general, resolution factor for closely elution peaks is selected as system suitability,If separation of impurities each other and from API peak is found to be satisfactory, there is no need to keep a resolution factor as system suitability parameter. In such cases only standard reproducibility and symmetry of standard peak can be adopted as system suitability requirement.
System Suitability holds significant importance in impurity analysis methods. It serves as a control mechanism, preventing out-of-trend or out-of-specification (OOT/OOS) outcomes in the event of a system suitability failure.
Notably, a failure in system suitability does not trigger an investigation. However, consistent failures in system suitability warrant an investigation into the method's functionality.
Therefore, careful configuration of system suitability parameters is imperative to prevent impurity failures caused by system errors. For instance, consider the scenario where two closely positioned impurity peaks could potentially merge due to slight variations in the column or mobile phase. Such a merger could result in a failure to meet specifications.
To illustrate, I have encountered a situation where two unknown impurities, individually calculated as 0.05% and 0.07% through acid degradation, remain separate peaks. Yet, when these peaks merge, the total becomes 0.12%, exceeding the specified limit of not more than 0.10%. In this context, a system suitability approach that reflects the separation of both impurities can effectively serve as a suitable solution.
Benefits of System Suitability
Ensures method Reliability and Consistency:
By monitoring key performance parameters, such as resolution, peak symmetry, and retention times, system suitability testing helps identify any deviations or inconsistencies that could affect the reliability of the method.
Detects Instrument Issues:
SST can reveal any problems or variations in the performance of the analytical instrument. This includes issues such as drift in instrument response, changes in sensitivity, or malfunctions in the instrument components.
Validates Method Performance:
SST provides evidence that the analytical method is performing as expected and meets predefined acceptance criteria.
Optimizes Method Condition:
Through SST , optimal method conditions can be established or fine-tuned. This includes parameter like column temperature, mobile phase composition, flow rate, and inj.volume.
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