Standard Operating Procedure for Inline UV Absorbance Monitoring in Biosimilar Manufacturing

Department	Biosimilars
SOP No.	SOP/BS/200/2025
Supersedes	SOP/BS/200/2022
Page No.	Page 1 of 9
Issue Date	04/05/2025
Effective Date	06/05/2025
Review Date	04/05/2026

1. Purpose

To define a GMP-compliant procedure for operating, calibrating, and maintaining inline UV absorbance sensors used for monitoring biosimilar protein concentration during chromatography and ultrafiltration processes.

2. Scope

This SOP applies to all inline UV detectors integrated with chromatography skids, TFF systems, and UF/DF units within biosimilar downstream purification operations.

3. Responsibilities

• Manufacturing: Operate and monitor inline UV systems during batch processing.
• Engineering: Calibrate and maintain UV sensors as per schedule.
• QA: Review UV absorbance data logs and deviations; verify calibration certificates.

4. Accountability

The Head of Manufacturing and Head of Engineering are accountable for ensuring the integrity and accuracy of inline UV absorbance monitoring systems.

5. Procedure

5.1 System Preparation and Verification

1. Ensure the UV detector is powered and connected to the skid HMI or SCADA interface.
2. Check that the correct wavelength (typically 280 nm for protein detection) is selected.
3. Verify that the system baseline is stable before starting the purification run.

5.2 Calibration and Standardization

1. Perform calibration using potassium dichromate standards at specified concentrations (Annexure-1).
2. Record absorbance values at 280 nm and validate linearity across the range (e.g., 0.1 to 2.0 AU).
3. Calibrate annually or as per manufacturer recommendation.
4. Document all calibration activity in Annexure-2.

5.3 Inline Monitoring During Operation

1. During chromatography or filtration, monitor the UV signal continuously.
2. Use UV trace to identify:
   • Peak elution windows
   • Breakthrough detection
   • End-of-run indication
3. Capture data in real-time using integrated data acquisition systems.
4. Compare peak profiles with batch standards to detect anomalies.

5.4 Signal Threshold and Trigger Points

1. Set UV absorbance thresholds in skid automation (e.g., 0.1 AU for elution start, 0.05 AU for elution end).
2. Ensure operator is trained on modifying or acknowledging UV-based triggers for fraction collection.
3. Confirm fractionation valves respond to UV threshold accurately.

5.5 Data Logging and Batch Record Entry

1. Ensure continuous UV data is logged in electronic batch record or SCADA system.
2. Export absorbance curves for archiving and review.
3. Log any deviation from expected UV pattern in Annexure-3.

5.6 Maintenance and Cleaning

1. Flush UV flow cell with WFI post-batch.
2. Use 0.1 M NaOH for weekly sanitization, followed by neutralization and rinse.
3. Inspect quartz cell for fouling or damage every month and clean if needed.

5.7 Deviation Handling

1. In case of signal loss, drift, or non-linearity:
   • Pause operation if required
   • Document incident (Annexure-3)
   • Switch to offline UV confirmation for critical process points

6. Abbreviations

• AU: Absorbance Unit
• UV: Ultraviolet
• SCADA: Supervisory Control and Data Acquisition
• WFI: Water for Injection

7. Documents

1. UV Calibration Standards Log – Annexure-1
2. UV Calibration Record – Annexure-2
3. UV Deviation Log – Annexure-3

8. References

• ICH Q8 – Pharmaceutical Development
• PDA TR 13 – Fundamentals of UV Monitoring in Biotech Processing
• FDA Guidance on PAT (Process Analytical Technology)

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: UV Calibration Standards Log

Date	Standard	Concentration (mg/mL)	Theoretical AU	Observed AU
04/05/2025	Potassium Dichromate	0.2	0.400	0.398

Annexure-2: UV Calibration Record

Date	Instrument ID	Wavelength	Status	Calibrated By
04/05/2025	UV-280X	280 nm	Pass	Ajay Verma

Annexure-3: UV Deviation Log

Date	Batch No.	Deviation	Impact	Action Taken
03/05/2025	BS-PUR-116	Signal Drop Mid-Run	Minor	Switched to offline UV check

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Updated calibration frequency and deviation logging format	Audit compliance