in-process and final product stages.

3. Responsibilities

• QC Analyst: Responsible for performing the pH testing using a calibrated pH meter.
• QC Supervisor: Reviews and verifies results.
• QA Officer: Ensures compliance with specifications before batch release.

4. Accountability

The Head of Quality Control is accountable for the execution and compliance of this SOP.

5. Procedure

5.1 Equipment and Materials

• Calibrated pH meter
• pH standard buffer solutions (4.01, 7.00, and 9.21)
• Beakers, pipettes, gloves, and clean wipes

5.2 Calibration of pH Meter

1. Switch on the pH meter and allow it to stabilize.
2. Calibrate using standard buffer solutions as per the instrument SOP.
3. Ensure a minimum two-point calibration (pH 4.01 and 7.00 or 7.00 and 9.21).
4. Record calibration data in the pH Meter Calibration Log (Annexure-1).

5.3 Sample Preparation

1. Withdraw a representative sample of the injectable product.
2. For powders, reconstitute using specified diluent per product monograph.
3. Allow the sample to reach room temperature (20°C to 25°C).

5.4 Testing Procedure

1. Rinse the electrode with distilled water and blot dry using lint-free tissue.
2. Immerse the electrode in the sample ensuring full contact with the solution.
3. Record the pH value once stabilized (typically within 30 seconds).
4. Rinse and dry the electrode after each sample.
5. Repeat testing in duplicate for accuracy.

5.5 Acceptance Criteria

The pH value should comply with the specifications mentioned in the approved product monograph or pharmacopoeia (e.g., USP, EP, IP).

5.6 Documentation

1. Record all readings in the pH Testing Log (Annexure-2).
2. Attach signed test report with Batch Release Form (Annexure-3).

6. Abbreviations

• SOP: Standard Operating Procedure
• QC: Quality Control
• pH: Potential of Hydrogen
• USP: United States Pharmacopeia
• EP: European Pharmacopoeia
• IP: Indian Pharmacopoeia

7. Documents

1. pH Meter Calibration Log – Annexure-1
2. pH Testing Log – Annexure-2
3. Batch Release Form – Annexure-3

8. References

• USP General Chapter <791> – pH
• EP 2.2.3 – Potentiometric Determination of pH
• IP – pH Determination Procedures

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation	QC Analyst	QC Manager	Head QA
Department	Quality Control	Quality Control	Quality Assurance

11. Annexures

Annexure-1: pH Meter Calibration Log

Date	Instrument ID	Buffer pH Used	Calibrated By	Remarks
18/06/2025	PHM-02	4.01 / 7.00	Ajay Deshmukh	Calibration OK

Annexure-2: pH Testing Log

Batch No.	Product	pH Value	Tested By	Date
CFT-124	Ceftriaxone Injection	6.5	Neha Patil	18/06/2025

Annexure-3: Batch Release Form

Product	Batch No.	pH Complies	Reviewed By	QA Release
Meropenem Injection	MERP-007	Yes	Sunita Reddy	Approved

Revision History

Revision Date	Revision No.	Details	Reason	Approved By
02/01/2022	1.0	Initial version	New SOP	QA Head
18/06/2025	2.0	Updated procedure and annexures	Periodic Review	QA Head