formulations, particularly during forced degradation and stability studies.

2. Scope

This SOP is applicable to Analytical Method Development (AMD) personnel responsible for degradation profiling of Active Pharmaceutical Ingredients (APIs) and drug products during method validation, stability testing, or investigational analysis.

3. Responsibilities

• Analytical Scientist: Performs LC-MS runs, analyzes spectra, and interprets fragmentation patterns.
• Method Development Chemist: Designs stress study protocols and identifies degradation peaks for characterization.
• QA Officer: Reviews final impurity profiles and ensures all unknown degradants are addressed per ICH Q3B and M7.
• Head – AMD: Approves final reports and supports regulatory submission readiness.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring compliance, data reliability, and scientific accuracy of the LC-MS-based degradation analysis process.

5. Procedure

5.1 Selection of Degraded Samples

1. Use samples exposed to stress conditions (acid/base hydrolysis, oxidation, heat, humidity, light) per ICH Q1A(R2).
2. Identify unknown degradation peaks from stability-indicating HPLC chromatograms.
3. Record RT, RRT, and peak area in Annexure-1: Degradation Peak Log.

5.2 Sample Preparation for LC-MS

1. Prepare sample solutions at appropriate concentrations (typically 10–50 µg/mL) using MS-compatible solvents (e.g., acetonitrile:water with 0.1% formic acid).
2. Filter through 0.22 µm PVDF membrane filters.
3. Use known impurity standards, if available, for comparison.

5.3 LC-MS Instrument Setup

1. Column: C18, 50 mm × 2.1 mm, 1.7 µm particle size.
2. Mobile Phase A: 0.1% Formic acid in water
3. Mobile Phase B: 0.1% Formic acid in acetonitrile
4. Flow rate: 0.3 mL/min; Injection volume: 5 µL
5. Run MS in ESI mode (positive and/or negative) based on compound polarity.
6. Enable full-scan mode (m/z 100–1000) followed by targeted MS/MS acquisition.

5.4 Data Acquisition and Interpretation

1. Acquire chromatogram and full-scan mass spectra for unknown peaks.
2. Determine the molecular ion [M+H]⁺ or [M–H]^–.
3. Run MS/MS for fragmentation pattern analysis.
4. Compare fragments with known degradation pathways, if applicable.
5. Document in Annexure-2: LC-MS Spectral Interpretation Sheet.

5.5 Structural Elucidation and Reporting

1. Propose possible structures using spectral library, software prediction, or literature data.
2. Assign unique impurity codes (e.g., DGP-UNK-01).
3. Summarize findings in Annexure-3: Unknown Degradation Product Report.
4. If structural alerts are found, refer to toxicology for assessment as per ICH M7.

6. Abbreviations

• API: Active Pharmaceutical Ingredient
• LC-MS: Liquid Chromatography-Mass Spectrometry
• ESI: Electrospray Ionization
• RT: Retention Time
• RRT: Relative Retention Time
• SOP: Standard Operating Procedure

7. Documents

1. Degradation Peak Log – Annexure-1
2. LC-MS Spectral Interpretation Sheet – Annexure-2
3. Unknown Degradation Product Report – Annexure-3

8. References

• ICH Q3B(R2) – Impurities in New Drug Products
• ICH Q1A(R2) – Stability Testing of New Drug Substances and Products
• ICH M7 – Assessment and Control of DNA Reactive Impurities

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Degradation Peak Log

Sample ID	RT (min)	RRT	Area %	Condition
STB-API-25	9.73	1.28	0.45%	Oxidative

Annexure-2: LC-MS Spectral Interpretation Sheet

m/z	Fragment	Interpretation
315	Base Peak	Molecular ion of degradation product
287	Loss of –COOH	Carboxylic acid degradation pathway

Annexure-3: Unknown Degradation Product Report

LC-MS analysis of oxidative stress sample revealed DGP-UNK-01 with m/z 315. Fragmentation consistent with sulfoxide formation. Structure proposed based on NMR correlation. No genotoxic alert. Logged for monitoring in future stability studies.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Enhanced scope to include MS/MS confirmation and ICH M7 guidance	Annual SOP Review