the susceptibility of molecules to light and ensure formulation integrity during shelf life under ICH Q1B conditions.

2. Scope

This procedure applies to all APIs and drug products developed by the Analytical Method Development (AMD) department, covering both solid and liquid dosage forms. The SOP includes testing under Option 1 (single light source) or Option 2 (combination of cool white and UV light).

3. Responsibilities

• Analytical Scientist: Designs study, selects analytical methods, and interprets degradation profiles.
• Lab Analyst: Conducts sample exposure, monitors conditions, and performs data analysis.
• QA Officer: Reviews protocol, study execution, and documentation for compliance.
• Head – AMD: Approves photostability method and final report for submission and regulatory review.

4. Accountability

The Head of AMD is accountable for ensuring all photostability studies are conducted under controlled conditions and in alignment with ICH Q1B guidelines, and that methods are scientifically validated for stability-indicating properties.

5. Procedure

5.1 Selection of Light Source and Exposure Conditions

1. Choose one of the following per ICH Q1B:
   • Option 1: Artificial daylight fluorescent lamp (≥1.2 million lux hours and ≥200 Wh/m² UV energy)
   • Option 2: Combination of cool white fluorescent and UV lamp (similar exposure)
2. Verify light intensity using calibrated lux and UV meters before and after exposure.

5.2 Sample Selection and Placement

1. Prepare the following samples:
   • Unprotected (directly exposed)
   • Protected control (wrapped in aluminum foil)
2. Use clear, amber, or primary container packaging depending on formulation type.
3. Spread solid samples in a thin layer in petri dishes; liquids to be placed in quartz cuvettes or transparent vials.

5.3 Exposure Setup and Monitoring

1. Place samples inside photostability chamber or enclosure with controlled ventilation and humidity.
2. Record environmental conditions (temperature, humidity, lux, and UV intensity) hourly.
3. Continue exposure until minimum 1.2 million lux hours and 200 Wh/m² UV are achieved.
4. Log exposure data in Annexure-1: Photostability Exposure Log.

5.4 Sample Analysis

1. Collect samples at:
   • Initial (0 hours)
   • Interim (optional: 6–12 hours)
   • Final exposure point
2. Analyze using validated HPLC or UPLC method suitable for detecting degradation peaks.
3. Compare retention time, assay %, and impurity profile with protected sample.
4. Assess peak purity using PDA detector or spectral overlays.
5. Document results in Annexure-2: Photostability Data Report.

5.5 Interpretation and Reporting

1. Acceptable degradation should range from 5–20% for method validation.
2. Identify and report any photolytic degradants if observed.
3. Conclude method’s specificity and ability to separate degradation products from API peak.
4. Prepare final report including chromatograms, conditions, and conclusions.

6. Abbreviations

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

7. Documents

1. Photostability Exposure Log – Annexure-1
2. Photostability Data Report – Annexure-2

8. References

• ICH Q1B – Photostability Testing of New Drug Substances and Products
• ICH Q2(R2) – Validation of Analytical Procedures
• USP <671> – Containers and Storage Conditions

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Photostability Exposure Log

Date	Time	Lux Reading	UV Intensity	Temperature (°C)	Humidity (%)	Analyst
18/05/2025	09:00	61000	8.5	25	60	Sunita Reddy

Annexure-2: Photostability Data Report

Sample ID	Time (hrs)	Assay (%)	% Degradation	Degradant Peaks	Peak Purity
API-PH-045	24	89.2	10.8	2 (RT 3.1, 6.7 min)	Pass

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Added PDA-based peak purity assessment and control sample requirements	Regulatory enhancement