Standard Operating Procedure for pCO₂ and pO₂ Monitoring in Bioreactor Operations for Biosimilars
| Department | Biosimilars |
|---|---|
| SOP No. | SOP/BS/083/2025 |
| Supersedes | SOP/BS/083/2022 |
| 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 monitoring partial pressure of carbon dioxide (pCO₂) and oxygen (pO₂) during bioreactor operations for biosimilar production, using inline sensors and off-line validation to ensure cell culture health and productivity.
2. Scope
This SOP applies to all bioreactor systems in upstream processing of biosimilars that utilize real-time pCO₂ and pO₂ monitoring via probes or external analyzers.
3. Responsibilities
- Bioprocess Technicians: Monitor and log pCO₂ and pO₂ values routinely and escalate deviations.
- Instrumentation Engineer: Calibrate and maintain gas sensors and analyzers.
- QA Personnel: Review gas level trends and verify control actions.
4. Accountability
The Production Head is accountable for maintaining accurate pCO₂/pO₂ profiles during bioreactor culture and ensuring adherence to validated ranges.
5. Procedure
5.1 Sensor Setup and Calibration
- Ensure pCO₂ and pO₂ sensors are installed, sterilized, and connected to the controller or SCADA system.
- Calibrate sensors as per SOP/BS/082/2025 before each batch or after any probe replacement.
- Verify baseline and slope using certified gas standards (5% CO₂, 21% O₂).
5.2 Online Monitoring
- Start recording pCO₂ and pO₂ levels once inoculation is complete.
- Typical acceptable values:
- pO₂: Maintain 30%–70% of air saturation
- pCO₂: Maintain below 100 mmHg (approx. 13.3 kPa)
- Monitor trends continuously and log data every 2–4 hours in Annexure-1.
- Adjust agitation, aeration, or CO₂ gassing based on deviations.
5.3 Off-line Validation (if required)
- Collect 5 mL of culture fluid and transfer to blood gas analyzer under sterile conditions.
- Compare off-line readings with inline sensor output to validate accuracy.
- Document comparative data in Annexure-2.
5.4 Corrective Action
- If pCO₂ exceeds limits:
- Increase headspace aeration or use alkaline base to counter acidification.
- If pO₂ drops:
- Increase stirrer speed, sparger airflow, or add pure O₂ as needed.
5.5 Documentation
- All readings must be recorded in Gas Monitoring Log (Annexure-1).
- Any interventions or parameter changes must be authorized and recorded.
6. Abbreviations
- pO₂: Partial Pressure of Oxygen
- pCO₂: Partial Pressure of Carbon Dioxide
- SCADA: Supervisory Control and Data Acquisition
- QA: Quality Assurance
7. Documents
- Gas Monitoring Log – Annexure-1
- Off-line Validation Record – Annexure-2
8. References
- USP <1046> – Cell Viability and Growth
- ICH Q8 – Pharmaceutical Development
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Gas Monitoring Log
| Date | Time | Batch No. | pO₂ (%) | pCO₂ (mmHg) | Action Taken | Operator |
|---|---|---|---|---|---|---|
| 04/05/2025 | 14:00 | BS-083-B01 | 54 | 87 | Normal | Rajesh Kumar |
Annexure-2: Off-line Validation Record
| Date | Sample ID | Inline pO₂ | Offline pO₂ | Inline pCO₂ | Offline pCO₂ | Remarks |
|---|---|---|---|---|---|---|
| 04/05/2025 | GAS-058 | 52% | 53% | 89 mmHg | 88 mmHg | Within limits |
Revision History:
| Revision Date | Revision No. | Revision Details | Reason for Revision | Approved By |
|---|---|---|---|---|
| 04/05/2025 | 2.0 | Added off-line comparison section and CO₂ intervention strategy | Process Enhancement |