USP 621 System sensitivity & Peak symmetry requirements updated

System sensitivity requirement is limited to impurities where a reporting threshold is specified and Peak symmetry requirement is waived if %RSD is part of system suitability test. The updated version of USP 621 <Chromatography> is published in USP Pharmacopeia forum on 1 November 2023.

1. System sensitivity: The requirement that the Limit of Quantitation (corresponding to S/N ratio of 10) is equal to or less than reporting threshold, is limited to Impurity analysis where a reporting threshold is specified in the monograph.
2. Peak Symmetry: The Peak symmetry requirement can be waived if determination of %RSD (Relative response factor) is part of system suitability test.  In current official chapter, peak symmetry (symmetry factor) for the peak used for quantification was defined as 0.8-1.8. Also now it is made explicit that It is only applicable for Organic impurities, Related substances and Assay tests.

These modifications are made in response to comments and clarifications received by USP and data showed that in some cases of current official monographs the requirements of System sensitivity and Peak Symmetry cannot be met.

The draft chapter 621<Chromatography> can be accessed on the Pharmacopeial Forum website and is open for comments till 31 January 2024. The changes are due to come in force in May 2025.

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