CEI-MS-13 — procedure

§4Procedure

The procedure below is written in the second person, which is the only place in the Institute's document set where that register is used. A procedure is an instruction and is written as one.

1. Select stress conditions from the analyte’s degradation chemistry as recorded in its monograph, rather than from a generic list. A methionine-containing peptide requires oxidative stress; an aspartate-adjacent sequence requires alkaline stress for aspartimide; a tryptophan-containing peptide requires photolytic stress.
2. Stress separate aliquots to a target degradation of 5 to 20 %. Degradation beyond 20 % generates secondary degradants that would not arise in real storage and produces a method validated against artefacts.
3. Analyse each stressed sample. Confirm that all degradant peaks are resolved from the analyte with resolution ≥ 1.5, or that unresolved species are identified and shown to be quantitatively insignificant.
4. Assess peak purity of the analyte in each stressed sample by diode-array spectral comparison across the peak. Record the purity angle against the purity threshold.
5. Identify each significant degradant by LC–MS and assign it to a degradation route.
6. Construct the mass balance: the sum of analyte and degradant areas, corrected for relative response where determined, should account for 95 to 105 % of the unstressed total.
7. Validate specificity, linearity, accuracy, precision, quantitation limit and robustness per ICH Q2(R2).
8. Report the stress conditions applied, the degradation achieved, the degradants identified, the peak-purity result and the mass balance.

References cited on this page

References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.

1. International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. ICH Q2(R2) Validation of Analytical Procedures. ICH Harmonised Guideline 2023;Step 4 version, 1 November 2023. identifier not held by the Institute

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