Biosimilars: SOP for Dissolved Oxygen (DO) Control in Bioreactor Operations – V 2.0
Standard Operating Procedure for Dissolved Oxygen (DO) Control in Bioreactor Operations for Biosimilar Manufacturing
| Department |
Biosimilars |
| SOP No. |
SOP/BS/070/2025 |
| Supersedes |
SOP/BS/070/2022 |
| Page No. |
Page 1 of 12 |
| Issue Date |
04/05/2025 |
| Effective Date |
06/05/2025 |
| Review Date |
04/05/2026 |
1. Purpose
To define the procedure for maintaining and controlling dissolved oxygen (DO) levels in bioreactor systems used in upstream biosimilar production, ensuring optimal cell growth and productivity under GMP conditions.
2. Scope
This SOP applies to all batch and fed-batch bioreactor systems, stainless steel or single-use, used for mammalian cell culture in biosimilar manufacturing from 10L to 2000L capacity.
3. Responsibilities
- Upstream Operators: Monitor DO levels, adjust cascade settings, and document all activities.
- Engineering Team: Calibrate DO probes and verify air/oxygen supply lines and sensors.
- QA Personnel: Review DO trends and deviation records.
4. Accountability
The Bioprocess Manager is accountable for ensuring DO levels are maintained within defined ranges throughout the culture process and that equipment is validated and compliant.
5. Procedure
5.1 DO Probe Calibration
- Calibrate the DO probe using a 2-point method (0% with nitrogen-saturated solution and 100% with air-saturated water).
- Document calibration details in Annexure-1 before starting batch.
5.2 DO Setpoint and Cascade Configuration
- Set DO control range to 40%–60% saturation unless otherwise defined in the batch record.
- Configure cascade sequence:
- Primary: Airflow rate increase
- Secondary: Agitation speed ramp-up
- Tertiary: Oxygen enrichment (pure O₂ addition)
- Ensure each step is within its validated range to prevent shear stress or oxygen toxicity.
5.3 Real-Time Monitoring
- Continuously monitor DO using bioreactor control software.
- Log DO every 2 hours in DO Monitoring Log (Annexure-2).
- Track correlation between DO and viable cell density (VCD) growth trends.
5.4 Alarm Management
- In case of deviation (DO < 35% or > 70%):
- Check gas flow rates, agitation settings, and probe functionality.
- Notify engineering if physical component failure is suspected.
- Trigger deviation report as per SOP/BS/050/2025.
5.5 Post-Culture Probe Handling
- Rinse probe with distilled water and store in storage solution (typically 0.1 M KCl).
- Record end-of-batch status in Annexure-3.
6. Abbreviations
- DO: Dissolved Oxygen
- GMP: Good Manufacturing Practice
- VCD: Viable Cell Density
- O₂: Molecular Oxygen
7. Documents
- DO Probe Calibration Log – Annexure-1
- DO Monitoring Log – Annexure-2
- End-of-Batch DO Summary – Annexure-3
8. References
- ICH Q8 – Pharmaceutical Development
- WHO TRS 1025 – Guidelines on Biological Manufacturing
- SOP/BS/050/2025 – Deviation Handling
9. SOP Version
Version: 2.0
10. Approval Section
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Approved By |
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11. Annexures
Annexure-1: DO Probe Calibration Log
| Probe ID |
Calibration Date |
Calibration Range |
Calibrated By |
| DO-BR-001 |
03/05/2025 |
0%–100% |
Sunita Reddy |
Annexure-2: DO Monitoring Log
| Date |
Time |
DO Setpoint (%) |
Actual DO (%) |
Remarks |
| 04/05/2025 |
14:00 |
50 |
49.6 |
Stable |
Annexure-3: End-of-Batch DO Summary
| Batch ID |
Final DO (%) |
Deviation Observed |
Corrective Action |
| BR-111 |
51.2 |
No |
N/A |
Revision History:
| Revision Date |
Revision No. |
Revision Details |
Reason for Revision |
Approved By |
| 04/05/2025 |
2.0 |
Added DO cascade strategy and Annexure-3 |
Process Enhancement |
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