EDQM publishes new FAQ on System Suitability Test (SST)

The EDQM has announced the addition of a new FAQ to its existing series, addressing the system suitability test (selectivity) in chromatographic assay procedures. This update comes in response to user inquiries received via the HelpDesk.

The new FAQ specifically references the phrase, “as described in the test for related substances with the following modifications,” which appears in many monographs. The answer clarifies that in such assays, the SST is part of the analytical procedure. Consequently, "the reference solution prepared for the selectivity test, as part of the purity test, must be analysed in the assay even if this solution is not expressly mentioned under ‘ASSAY’."

In a press relase dated 17 December 2024, the EDQM writes: "This addition is expected to enhance the support to users by clarifying the SST requirements that apply to assays by chromatographic procedures when an analytical procedure similar to the related substances test is used."