Standard Operating Procedure for Tangential Flow Filtration (TFF) in Bioreactor Operations for Biosimilars

Department	Biosimilars
SOP No.	SOP/BS/089/2025
Supersedes	SOP/BS/089/2022
Page No.	Page 1 of 12
Issue Date	04/05/2025
Effective Date	06/05/2025
Review Date	04/05/2026

1. Purpose

To outline the procedure for executing Tangential Flow Filtration (TFF) to concentrate and perform buffer exchange on clarified cell culture supernatant as part of upstream/downstream transition in biosimilar production.

2. Scope

This SOP applies to all operations involving hollow fiber or cassette-based TFF systems used for concentrating protein-rich harvest and performing diafiltration prior to chromatography.

3. Responsibilities

• Process Operator: Assemble, operate, and monitor the TFF system.
• Maintenance Team: Verify calibration of flow meters, pressure gauges, and pumps.
• QA Officer: Review TFF batch records and ensure adherence to validated protocols.

4. Accountability

The Upstream/Downstream Lead is accountable for ensuring TFF operations meet process specifications and GMP requirements.

5. Procedure

5.1 System Setup

1. Ensure cleaning and sanitization of TFF system is completed as per equipment SOP.
2. Install membrane cassettes or hollow fibers with correct molecular weight cut-off (e.g., 30 kDa for mAbs).
3. Connect retentate, permeate, and feed lines using sanitary tri-clamp fittings.

5.2 Preconditioning

1. Flush membranes with WFI to remove preservatives and equilibrate with target buffer (e.g., PBS, Tris).
2. Record membrane lot numbers, surface area, and pre-use integrity check values in Annexure-1.

5.3 Filtration Operation

1. Load clarified harvest into feed tank and initiate TFF at:
   • Transmembrane Pressure (TMP): 1.0–2.0 bar
   • Crossflow Rate: 300–500 L/m²/h
2. Monitor:
   • Retentate volume and concentration
   • Permeate clarity and flow rate
   • pH and conductivity (if performing diafiltration)

5.4 Diafiltration (if applicable)

1. After concentration, initiate diafiltration by adding buffer at feed inlet and collecting permeate until 5–10 diafiltration volumes are exchanged.
2. Confirm final buffer conditions via pH/conductivity measurements.

5.5 Completion and Cleaning

1. Stop system, drain product into receiving tank labeled with batch ID.
2. Flush membranes and record post-use integrity check.
3. Label used membranes for single-use disposal or clean-in-place if reusable.

5.6 Documentation

1. Record all critical parameters in Annexure-2: TFF Process Log.
2. Any deviation from standard flow or pressure must be investigated and documented.

6. Abbreviations

• TFF: Tangential Flow Filtration
• TMP: Transmembrane Pressure
• WFI: Water for Injection
• PBS: Phosphate Buffered Saline

7. Documents

1. Membrane Loading Log – Annexure-1
2. TFF Process Log – Annexure-2

8. References

• ICH Q8 – Pharmaceutical Development
• WHO GMP Annex 2 – Biotech Product Guidelines

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Membrane Loading Log

Date	Batch No.	Membrane Type	MWCO (kDa)	Lot No.	Surface Area (m²)	Pre-Use Check	Operator
04/05/2025	BS-089-B01	Flat-sheet	30	TF-7711	0.5	Pass	Rajesh Kumar

Annexure-2: TFF Process Log

Time	TMP (bar)	Flow Rate (L/hr)	Retentate Volume (L)	Permeate Volume (L)	pH	Conductivity (mS/cm)	Remarks
10:30	1.5	420	8.4	5.0	7.2	12.5	Within spec

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
04/05/2025	2.0	Added diafiltration and integrity test instructions	Process enhancement