products under controlled light exposure conditions.

2. Scope

This procedure applies to the Analytical Method Development (AMD) team responsible for conducting forced degradation and stability-indicating method development for photolabile substances as per ICH Q1B guidelines.

3. Responsibilities

• Analytical Scientist: Develops and executes the photostability protocol and evaluates degradation behavior.
• Instrumentation Chemist: Calibrates and maintains light exposure chambers as per standard intensity parameters.
• QA Officer: Reviews photostability method reports and ensures regulatory alignment.
• Head – AMD: Approves protocols and final reports for submission or inclusion in regulatory filings.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring all photostability testing methods are scientifically justified, validated, and in compliance with ICH and WHO guidelines.

5. Procedure

5.1 Selection of Samples

1. Use API and/or finished product batches representative of development lots.
2. Samples should be of sufficient quantity and purity, packaged in standard and light-protective containers (e.g., amber vials).
3. Document selection in Annexure-1: Sample Allocation Log.

5.2 Light Source and Exposure Setup

1. Use a validated photostability chamber fitted with:
   • Cool white fluorescent lamps (≥ 1.2 million lux hours)
   • Near UV lamps (≥ 200 watt hours/m²)
2. Ensure spectral output and uniformity conform to ICH Q1B Option 2.
3. Record environmental parameters in Annexure-2: Light Exposure Log.

5.3 Sample Placement and Duration

1. Expose the sample in:
   • Clear containers for test
   • Light-protected containers (wrapped in aluminum foil) as control
2. Distribute samples uniformly in the exposure area to avoid shadowing.
3. Expose for the required light dose (e.g., 1.2 million lux hours + 200 Wh/m² UV) over 1–7 days.

5.4 Analytical Evaluation

1. Analyze exposed and control samples using validated HPLC or UPLC methods.
2. Compare chromatographic profiles for new peaks, peak purity, and loss of assay content.
3. Calculate percent degradation and document in Annexure-3: Degradation Assessment Sheet.

5.5 Method Development and Validation

1. Develop a stability-indicating method that resolves degradation products from the main peak.
2. Validate the method for specificity, linearity, accuracy, precision, and robustness per ICH Q2(R2).
3. Prepare a validation summary in Annexure-4: Method Validation Summary.

5.6 Reporting and Interpretation

1. Prepare a summary of:
   • Chromatographic observations
   • Spectral purity results
   • Degradation pathway hypothesis
2. Assess the need for protective packaging and revise product specifications accordingly.
3. Compile results into Annexure-5: Photostability Testing Report.

6. Abbreviations

• API: Active Pharmaceutical Ingredient
• ICH: International Council for Harmonisation
• HPLC: High Performance Liquid Chromatography
• UPLC: Ultra Performance Liquid Chromatography
• SOP: Standard Operating Procedure

7. Documents

1. Sample Allocation Log – Annexure-1
2. Light Exposure Log – Annexure-2
3. Degradation Assessment Sheet – Annexure-3
4. Method Validation Summary – Annexure-4
5. Photostability Testing Report – Annexure-5

8. References

• ICH Q1B – Photostability Testing of New Drug Substances and Products
• ICH Q2(R2) – Validation of Analytical Procedures
• WHO Technical Report Series – Stability Testing Guidelines

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Sample Allocation Log

Date	Sample ID	Batch No.	Assigned For	By
18/05/2025	PHO-API-25	A23/101	Photostability Study	Sunita Reddy

Annexure-2: Light Exposure Log

Date Started	Date Completed	Lux Hours	UV Exposure	Chamber ID
18/05/2025	25/05/2025	1.24 million	212 Wh/m2	PHO-CH-01

Annexure-3: Degradation Assessment Sheet

Sample ID	Assay Before	Assay After	% Degradation	New Peaks
PHO-API-25	99.2%	95.7%	3.5%	Yes

Annexure-4: Method Validation Summary

The photostability-indicating method showed specificity with separation of all degradants, linearity (r² ≥ 0.999), and accuracy within 98–102% recovery. Precision RSD ≤ 2.0%. Method validated as per ICH Q2(R2).

Annexure-5: Photostability Testing Report

Photostability study confirmed API degradation under light exposure with formation of three major degradation products. Recommended use of light-protective packaging. Stability-indicating HPLC method validated and implemented.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Expanded validation criteria and UV exposure monitoring per ICH Q1B	Annual SOP Review