Standard Operating Procedure for Testing Antioxidant Stability in Creams
| Department | Creams |
|---|---|
| SOP No. | SOP/CRM/137/2025 |
| Supersedes | SOP/CRM/137/2022 |
| Page No. | Page 1 of 5 |
| Issue Date | 21/01/2026 |
| Effective Date | 26/01/2026 |
| Review Date | 21/01/2027 |
1. Purpose
The purpose of this SOP is to define the procedure for testing antioxidant stability in cream formulations. Antioxidants are added to cream products to prevent oxidative degradation of active ingredients, which can reduce product efficacy and shelf life. This SOP ensures that the antioxidant content remains stable and effective over time.
2. Scope
This SOP applies to all cream formulations that contain antioxidant ingredients. It includes procedures for testing the stability of antioxidants in finished cream products, typically during accelerated stability testing and during long-term storage.
3. Responsibilities
- Production Team: Responsible for ensuring that the correct concentration of antioxidants is incorporated into the formulation and that the cream is produced under controlled conditions.
- Quality Control (QC) Team: Responsible for conducting antioxidant stability tests using validated methods, and ensuring that the results meet the required specifications.
- Quality Assurance (QA) Team: Responsible for reviewing and approving the antioxidant stability test results to ensure compliance with regulatory standards and internal specifications.
4. Accountability
The QC Manager is accountable for ensuring that antioxidant stability testing is performed in accordance with this SOP. The Production Supervisor is responsible for providing representative samples for testing. The QA Manager ensures that the results are reviewed and approved in compliance with GMP and regulatory standards.
5. Procedure
5.1 Pre-Test Preparation
- Ensure that the necessary equipment for antioxidant stability testing is available, including a UV-Visible spectrophotometer, HPLC system, and suitable solvents for sample preparation.
- Ensure that the testing environment is controlled and that all equipment is calibrated according to the manufacturer’s instructions.
- Review the batch record to confirm the formulation details, antioxidant content, and the antioxidants used in the product.
5.2 Sample Collection
- Collect a representative sample of the finished cream formulation for antioxidant stability testing. Ensure that the sample is homogenous and free from contamination.
- Label the sample with the batch number, sample ID, sampling date, and type of antioxidant used in the formulation to ensure traceability during testing.
- Ensure that the sample is taken from fully formulated and sealed cream products, which are ready for packaging.
5.3 Antioxidant Stability Testing Procedure
- Conduct the following tests to assess the stability of antioxidants in the cream formulation:
- UV-Visible Spectrophotometry: Measure the absorbance of the sample at the specific wavelength associated with the antioxidant compound. This will help monitor any reduction in antioxidant concentration over time.
- High-Performance Liquid Chromatography (HPLC): Use HPLC to quantify the concentration of the antioxidant in the cream formulation at different time intervals (e.g., 0, 7, 14, 21, and 28 days). Compare the concentration with the initial baseline to assess stability.
- Accelerated Stability Testing: Store the cream samples under accelerated conditions (e.g., elevated temperature and humidity) and measure the antioxidant levels over a short period, typically 3 to 6 months, to simulate long-term storage.
- Record the results of each test, including the concentration of the antioxidant at each time point, in the Antioxidant Stability Testing Log (Annexure-1).
5.4 Interpretation of Results
- Compare the antioxidant concentration at each time point with the initial concentration. A significant decrease in the antioxidant concentration (typically ≥10% reduction) over time indicates instability.
- If the antioxidant stability test passes, with no significant reduction in antioxidant levels, mark the test as “Pass” in the Antioxidant Stability Testing Log (Annexure-1) and proceed with the next stage of production or release.
- If the test fails, with a significant decrease in antioxidant concentration, mark the result as “Fail” and investigate the cause of the instability, such as formulation issues or improper storage conditions.
5.5 Post-Test Activities
- Record all test results, including batch number, sample ID, antioxidant concentration, test conditions, and any corrective actions taken, in the Antioxidant Stability Testing Log (Annexure-1).
- If the antioxidant concentration does not meet the required specifications, initiate corrective actions, such as adjusting the antioxidant concentration, modifying the formulation, or improving storage conditions. Re-test the sample after corrective actions.
- Submit the test results to the QA team for review and approval to ensure compliance with internal and regulatory standards.
5.6 Documentation and Record-Keeping
- Ensure that all antioxidant stability testing records are complete, accurate, and securely stored. This includes the Antioxidant Stability Testing Log (Annexure-1) and the Deviation Log (Annexure-2) for failed tests.
- Retain all records for a minimum of two years or as required by regulatory guidelines.
- Ensure that records are reviewed and approved by the Quality Assurance team to verify compliance with GMP standards and regulatory requirements.
6. Abbreviations
- GMP: Good Manufacturing Practices
- QC: Quality Control
- QA: Quality Assurance
- PPE: Personal Protective Equipment
- HPLC: High-Performance Liquid Chromatography
- UV: Ultraviolet
7. Documents
- Annexure-1: Antioxidant Stability Testing Log
- Annexure-2: Deviation Log
8. References
- Good Manufacturing Practices (GMP) Guidelines – 21 CFR Part 211
- International Conference on Harmonisation (ICH) Q7 – Good Manufacturing Practice for Active Pharmaceutical Ingredients
- Pharmacopeial Monographs for Antioxidant Testing
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Antioxidant Stability Testing Log
| Batch Number | Sample ID | Test Date | Antioxidant Concentration (%) | Operator |
|---|---|---|---|---|
| 12345 | S-001 | 21/01/2026 | 5.2% | John Doe |
Annexure-2: Deviation Log
| Deviation Date | Batch Number | Deviation Description | Corrective Action Taken | Operator |
|---|---|---|---|---|
| 21/01/2026 | 12345 | Decrease in antioxidant concentration | Reformulated and re-tested | Jane Smith |
Revision History:
| Revision Date | Revision No. | Revision Details | Reason for Revision | Approved By |
|---|---|---|---|---|
| 01/03/2024 | 1.0 | Initial Version | New SOP Creation | QA Head |
| 01/03/2025 | 2.0 | Format Revision and Updates | Standardization of Document | QA Head |