Standard Operating Procedure for Harvest Clarification Using Depth Filtration in Biosimilar Manufacturing

Department	Biosimilars
SOP No.	SOP/BS/151/2025
Supersedes	SOP/BS/151/2022
Page No.	Page 1 of 9
Issue Date	04/05/2025
Effective Date	06/05/2025
Review Date	04/05/2026

1. Purpose

To establish a standardized procedure for clarifying harvested cell culture fluid using depth filtration systems prior to downstream purification steps in biosimilar manufacturing under GMP conditions.

2. Scope

This SOP applies to harvest clarification of mammalian cell culture processes in biosimilar production facilities using depth filters in single-use or stainless steel systems.

3. Responsibilities

• Production: Execute harvest and filtration operation, ensure equipment integrity and documentation.
• QA: Review batch records, filtration logs, and authorize product transfer to DSP.
• Engineering: Maintain filter integrity testing devices and associated support systems.

4. Accountability

The Manufacturing Head is accountable for ensuring compliance with this SOP during the harvest clarification stage and for reporting deviations to QA.

5. Procedure

5.1 Preparation and Pre-Use Checks

1. Verify the batch number, harvest vessel, and scheduled time of clarification.
2. Ensure filter lot number, pore grade, and capacity match the BMR specifications.
3. Check:
   • Filtration unit cleanliness
   • Filter integrity test (if applicable)
   • Drainage and venting ports are closed

5.2 Filter Setup

1. Connect the harvest vessel outlet to the inlet of the depth filter using sterile single-use tubing or cleaned stainless steel lines.
2. Connect the filter outlet to the clarified product collection vessel (e.g., bag or tank).
3. Ensure flow direction arrows align with setup as per manufacturer specification.

5.3 Filtration Operation

1. Open the transfer valve and begin filtration using controlled peristaltic or diaphragm pump.
2. Maintain a pressure not exceeding 1.5 bar (22 psi).
3. Monitor:
   • Inlet and outlet pressure
   • Flow rate (L/min)
   • Turbidity at outlet (optional inline sensor)
4. Stop filtration if pressure exceeds limits or filtrate turbidity increases above 25 NTU.

5.4 Completion and Post-Filtration Handling

1. Flush the filter with 1–2 L of WFI to maximize recovery (if allowed in protocol).
2. Disconnect all lines aseptically and cap the outlets of the clarified product container.
3. Record total volume processed, duration, and final pressure readings in Annexure-1.

5.5 Filter Integrity Testing (if applicable)

1. Perform bubble point or water intrusion test using certified device.
2. Record results in Annexure-2: Filter Integrity Test Log.

5.6 Deviation Management

1. Document any anomalies such as:
   • Filter rupture
   • High differential pressure
   • Turbidity spike
2. Inform QA and raise deviation report as per SOP for deviation handling.

6. Abbreviations

• WFI: Water for Injection
• NTU: Nephelometric Turbidity Units
• BMR: Batch Manufacturing Record
• QA: Quality Assurance

7. Documents

1. Harvest Clarification Log – Annexure-1
2. Filter Integrity Test Log – Annexure-2

8. References

• WHO TRS 999 – GMP for Biotherapeutic Products
• ICH Q7 – GMP for Active Pharmaceutical Ingredients
• EU GMP Annex 1 – Manufacture of Sterile Medicinal Products

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Harvest Clarification Log

Date	Batch No.	Filter Lot	Volume (L)	Start Time	End Time	Final Pressure (psi)	Operator
04/05/2025	BS-UB-076	DF-1123A	110	10:00	11:15	18	Sunita Reddy

Annexure-2: Filter Integrity Test Log

Date	Filter ID	Test Type	Result	Pass/Fail	Technician
04/05/2025	DF-1123A	Bubble Point	3.2 bar	Pass	Ajay Verma

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
04/05/2025	2.0	Included WFI flush and turbidity monitoring steps	Process improvement