Standard Operating Procedure for pH Testing of Final Elixir Product
| Department | Elixir Department |
|---|---|
| SOP No. | SOP/ELX/214/2025 |
| Supersedes | SOP/ELX/214/2022 |
| Page No. | Page 1 of 7 |
| Issue Date | 11/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 11/04/2026 |
1. Purpose
To lay down a standardized method for the accurate determination of pH in the final elixir formulation to ensure product stability, patient safety, and compliance with approved specifications.
2. Scope
This SOP is applicable to the Quality Control Department for the analysis of final elixir batches prior to release using a calibrated pH meter.
3. Responsibilities
- QC Analyst:
- Perform pH testing as per method and record results.
- QC Supervisor:
- Verify results and check instrument calibration status.
- QA Officer:
- Ensure compliance with specifications and documentation practices.
4. Accountability
The QC Head is accountable for the execution and review of pH results. QA is responsible for approval and regulatory compliance.
5. Procedure
5.1 Preparation
- Ensure the pH meter is calibrated on the day of analysis using pH 4.0, 7.0, and 9.2 buffer solutions.
- Record calibration details
in the Instrument Calibration Logbook.
Clean and dry the sample beakers and electrodes before use.
5.2 Sampling
- Withdraw approximately 20–30 mL of well-mixed final product sample using a clean pipette or beaker.
- Allow the sample to equilibrate to room temperature (25 ± 2°C) before testing.
5.3 pH Testing Procedure
- Rinse the electrode with distilled water and blot dry with lint-free tissue.
- Immerse the electrode into the sample ensuring complete submersion of the bulb.
- Stir gently and wait for the reading to stabilize (approx. 30–60 seconds).
- Record the pH value displayed by the meter.
- Remove the electrode, rinse, and store as per manufacturer’s instructions.
5.4 Acceptance Criteria
- The pH should be within the range specified in the product specification sheet (typically 5.0–7.5 for oral elixirs unless otherwise defined).
- Deviation must be reported and investigated as per the deviation management SOP.
5.5 Documentation
- Record the result in the pH Test Logbook (Annexure-1).
- Attach a copy to the corresponding Batch Manufacturing Record (BMR).
- Ensure details include:
- Batch Number
- Date and Time of Testing
- Instrument ID
- Sample Temperature
- Tested By / Verified By
6. Abbreviations
- pH: Potential of Hydrogen
- SOP: Standard Operating Procedure
- QC: Quality Control
- QA: Quality Assurance
- BMR: Batch Manufacturing Record
7. Documents
- pH Test Logbook (Annexure-1)
- Instrument Calibration Logbook
- Batch Manufacturing Record (BMR)
8. References
- USP General Chapter <791> – pH
- 21 CFR Part 211.160 – Laboratory Controls
- 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 Logbook
| Date | Batch No. | Sample Temp (°C) | Instrument ID | Observed pH | Specification | Tested By | Verified By |
|---|---|---|---|---|---|---|---|
| 11/04/2025 | ELX-0425-032 | 25.2 | PHM-03 | 6.7 | 6.0 – 7.5 | Rajesh Kumar | Sunita Reddy |
Revision History:
| Revision Date | Revision No. | Revision Details | Reason for Revision | Approved By |
|---|---|---|---|---|
| 01/01/2024 | 1.0 | Initial Release | New SOP | QA Head |
| 11/04/2025 | 2.0 | Updated with equilibration and verification steps | GMP Compliance | QA Head |