Standard Operating Procedure for Use of Magnetic Stirrer in Pilot Batches
| Department | Elixir Department |
|---|---|
| SOP No. | SOP/ELX/127/2025 |
| Supersedes | SOP/ELX/127/2022 |
| Page No. | Page 1 of 10 |
| Issue Date | 11/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 11/04/2026 |
1. Purpose
To establish a standardized procedure for the correct and safe use of magnetic stirrers during the preparation of pilot-scale elixir batches to ensure consistent mixing, uniformity, and reproducibility of experimental results.
2. Scope
This SOP applies to all magnetic stirrers used in the Elixir Department’s formulation development area during pre-formulation trials, pilot batch preparation, or experimental optimization studies.
3. Responsibilities
- Formulation Scientist/Research Associate:
- Operate magnetic stirrer and monitor mixing parameters.
- Ensure cleanliness and calibration of equipment before use.
- Formulation Supervisor:
- Verify operation and document mixing parameters.
- QA Officer:
- Review batch documentation and ensure proper handling.
4. Accountability
The Head of Formulation Development is accountable for ensuring that magnetic stirrers are operated in accordance with GMP and scientific protocols.
5. Procedure
5.1 Pre-Use Checks
- Ensure the magnetic stirrer is labeled “CLEANED”
and within calibration due date.
Verify that the platform is flat, clean, and stable.
Check the stir bar (magnetic flea) for cleanliness and cracks; use only sterile stir bars for sensitive batches.
5.2 Setup and Operation
- Place the beaker or vessel with the solution on the center of the magnetic stirrer platform.
- Gently lower the magnetic stir bar into the liquid.
- Switch on the stirrer and slowly increase speed to the desired RPM (as per batch sheet or experiment protocol).
- If equipped with a hot plate, set the desired temperature (if heating is required) and monitor closely.
- Observe vortex formation and ensure the stir bar is rotating smoothly without jumping.
5.3 Monitoring
- Record RPM, temperature (if heated), and mixing duration in the Magnetic Stirrer Log (Annexure-1).
- Check for:
- Phase separation or foaming
- Unusual noises or vibrations
- Settling of solids or incomplete mixing
5.4 Post-Use Cleaning
- Switch off the stirrer and disconnect the plug.
- Remove the magnetic stir bar using a clean spatula or magnetic retriever.
- Clean both the stir bar and the platform using lint-free wipes and validated cleaning solution.
- Dry with clean compressed air or allow to air dry before storing.
- Affix the “TO BE CLEANED” or “CLEANED” label as applicable.
5.5 Precautions
- Never operate the stirrer without a container or liquid on the platform.
- Do not use damaged or cracked stir bars.
- Avoid excessive RPMs that may lead to spillage or magnetic disconnection.
- Ensure the hot plate (if present) is completely cooled before touching or cleaning.
6. Abbreviations
- SOP: Standard Operating Procedure
- QA: Quality Assurance
- RPM: Revolutions Per Minute
7. Documents
- Magnetic Stirrer Log (Annexure-1)
- Cleaning Checklist
- Pilot Batch Sheet
8. References
- ICH Q8 – Pharmaceutical Development
- 21 CFR Part 211 – GMP for Finished Pharmaceuticals
- Internal R&D Cleaning SOP (Ref: SOP/RD/007/2025)
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Magnetic Stirrer Log
| Date | Batch/Trial ID | Equipment ID | RPM | Temperature (if any) | Start Time | End Time | Operator | Remarks |
|---|---|---|---|---|---|---|---|---|
| 11/04/2025 | PB-ELX-003 | MS-01 | 500 | Ambient | 10:00 | 10:30 | Sunita Reddy | Uniform Mixing |
Revision History:
| Revision Date | Revision No. | Revision Details | Reason for Revision | Approved By |
|---|---|---|---|---|
| 01/01/2024 | 1.0 | Initial SOP Release | New SOP | QA Head |
| 11/04/2025 | 2.0 | Included monitoring log and updated cleaning steps | Process Improvement | QA Head |