Procedure for Performing In-Process pH Tests
| Department | Quality Control (QC)/Production |
|---|---|
| SOP No. | SOP/Ointment/076 |
| Supersedes | V 1.0 |
| Page No. | Page X of Y |
| Issue Date | [Insert Issue Date] |
| Effective Date | [Insert Effective Date] |
| Review Date | [Insert Review Date] |
1. Purpose
The purpose of this Standard Operating Procedure (SOP) is to define the method for performing in-process pH tests during ointment manufacturing. pH testing ensures product stability, efficacy, and compliance with predefined specifications.
2. Scope
This SOP applies to all personnel in the Quality Control (QC) and Production departments responsible for in-process pH testing of ointments during manufacturing.
3. Responsibilities
- Quality Control Analyst: Conducts in-process pH tests and records results.
- Production Operator: Provides in-process samples for testing.
- Production Supervisor: Ensures adherence to pH monitoring protocols.
- Quality Assurance (QA) Personnel: Reviews and approves pH test records.
4. Accountability
The QC and QA Managers are accountable for ensuring in-process pH tests are performed and documented as per GMP and regulatory requirements.
5. Procedure
5.1 Equipment and Materials
- Calibrated digital pH meter
- Glass beakers (100 mL, 250 mL)
- Magnetic stirrer (if required)
- pH buffer solutions (pH 4.0, 7.0, and 10.0)
- Distilled water
- Sampling containers
- pH Test Log
5.2 Pre-Test Preparations
- Ensure the pH meter is calibrated using standard buffer solutions.
- Rinse the electrode with distilled water before testing.
- Prepare fresh ointment samples for analysis.
- Ensure samples are maintained at the required testing temperature (typically 25°C ±
2°C).
5.3 pH Testing Procedure
5.3.1 Sample Preparation
- Weigh an appropriate amount of ointment (e.g., 1 g – 2 g).
- Disperse the sample in 10-20 mL of distilled water in a beaker.
- Stir the mixture gently to create a uniform suspension.
- Allow the mixture to stabilize for 5 minutes.
5.3.2 Measuring pH
- Immerse the pH meter electrode into the sample.
- Ensure the electrode is fully submerged without touching the beaker.
- Wait for a stable reading (approximately 30-60 seconds).
- Record the pH value in the pH Test Log.
5.4 Acceptance Criteria
- The pH of the ointment must be within the predefined specification range (e.g., 5.5 – 7.5).
- If the pH deviates from the acceptable range, report to the Production Supervisor immediately.
- Adjust the formulation as required (e.g., adding buffer solutions or pH-adjusting agents).
5.5 Post-Test Procedure
- Rinse the pH electrode with distilled water after each test.
- Store the electrode in the recommended storage solution.
- Ensure all pH test results are documented in the pH Test Log.
- QA personnel must review and approve pH test reports before batch release.
6. Abbreviations
- GMP – Good Manufacturing Practices
- QA – Quality Assurance
- QC – Quality Control
- pH – Potential of Hydrogen
7. Documents
- pH Test Log (Annexure-1)
- Batch Release Report (Annexure-2)
8. References
- WHO GMP Guidelines for Pharmaceutical Manufacturing
- USP <791> – pH Measurement
- ICH Q6A – Specifications: Test Procedures and Acceptance Criteria
9. SOP Version
Version 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: pH Test Log
| Date | Batch Number | Sample ID | pH Value | Acceptance Criteria | Result | Verified By |
|---|---|---|---|---|---|---|
| 01/02/2025 | OINT-101 | SMP-001 | 6.2 | 5.5 – 7.5 | Pass | QA Officer |
| 01/02/2025 | OINT-102 | SMP-002 | 7.1 | 5.5 – 7.5 | Pass | QA Officer |
Annexure-2: Batch Release Report
| Date | Batch Number | pH Test | Acceptance Criteria | Result | Final Status | Approved By |
|---|---|---|---|---|---|---|
| 01/02/2025 | OINT-101 | pH Measurement | 5.5 – 7.5 | 6.2 | Approved | QA Head |
| 01/02/2025 | OINT-102 | pH Measurement | 5.5 – 7.5 | 7.1 | Approved | QA Head |
12. Revision History:
| Revision Date | Revision No. | Details of Revision | Reason for Revision | Approved By |
|---|---|---|---|---|
| 01/01/2024 | 1.0 | Initial Version | New SOP | QA Head |
| 01/02/2025 | 2.0 | Updated SOP Format | Standardization of Document | QA Head |