API Manufacturing: SOP for Use of Conductivity Meter in API Plant – V 2.0

Standard Operating Procedure for Use of Conductivity Meter in API Manufacturing

Department	API Manufacturing
SOP No.	SOP/API/089/2025
Supersedes	SOP/API/089/2022
Page No.	Page 1 of 10
Issue Date	13/04/2025
Effective Date	15/04/2025
Review Date	13/04/2026

1. Purpose

To define the procedure for using conductivity meters in API manufacturing processes to measure and monitor the conductivity of solutions during synthesis, purification, and equipment cleaning to ensure process control and GMP compliance.

2. Scope

This SOP applies to all conductivity meters used within the API manufacturing facility for in-process checks, water quality testing, and final rinse

conductivity monitoring during cleaning validation.

3. Responsibilities

Production Operator: Operate the conductivity meter and perform measurements as per batch and cleaning procedures.
QC Analyst: Verify calibration and results as needed for analytical or compliance purposes.
Engineering: Maintain and service instruments per schedule.
QA Officer: Review and retain conductivity measurement records.

4. Accountability

Production Head is accountable for proper usage and timely calibration. QA Head is responsible for ensuring data integrity and regulatory compliance.

5. Procedure

5.1 Instrument Check and Calibration

Verify calibration status before use. Calibration must be performed daily using certified standards (e.g., 84 µS/cm, 1413 µS/cm).
Record calibration details in the Conductivity Meter Calibration Log (refer Annexure-1).

5.2 Sample Collection

Collect process or cleaning solution samples in clean, dry glass beakers or plastic containers (non-reactive).
Ensure sampling point is flushed and representative of the bulk material.

5.3 Conductivity Measurement

Switch ON the instrument and allow stabilization for 5 minutes.
Rinse probe with distilled water and blot dry with lint-free tissue.
Immerse probe in sample ensuring full submersion of sensors.
Allow reading to stabilize (typically 30–60 seconds).
Record conductivity in µS/cm or mS/cm, along with temperature if auto-compensated.

5.4 Post-Measurement Cleaning and Storage

Rinse probe with distilled water after each use.
Store probe as per manufacturer’s instructions (e.g., in protective cap with storage solution).
Turn off the device when not in use.

5.5 Acceptance Criteria and Deviations

Refer to the BMR or cleaning protocol for conductivity limits (e.g., NMT 10 µS/cm for final rinse).
If out of limits, repeat measurement or escalate as deviation to QA.

5.6 Documentation

Enter results in the Conductivity Measurement Log (Annexure-2) and in-process or cleaning record.
Include date, time, batch number, sample type, and operator initials.

6. Abbreviations

SOP: Standard Operating Procedure
QA: Quality Assurance
QC: Quality Control
BMR: Batch Manufacturing Record
µS/cm: Microsiemens per centimeter

7. Documents

Conductivity Meter Calibration Log (Annexure-1)
Conductivity Measurement Log (Annexure-2)
Batch Manufacturing Record / Cleaning Record

8. References

ICH Q7 – Good Manufacturing Practice for Active Pharmaceutical Ingredients
USP <645> – Water Conductivity
21 CFR Part 211 – US FDA GMP 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: Conductivity Meter Calibration Log

Date	Meter ID	Buffer Standard	Expected Value	Observed Value	Performed By	Remarks
13/04/2025	CD-101	1413 µS/cm	1413	1412		Pass

Annexure-2: Conductivity Measurement Log

Date	Batch No.	Stage	Reading (µS/cm)	Temperature (°C)	Measured By	Remarks
13/04/2025	API-20250413	Final Rinse	6.4	26		Complies

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
01/01/2022	1.0	Initial SOP Release	Instrument Usage Control	QA Head
13/04/2025	2.0	Updated calibration criteria and sample handling	Process Improvement	QA Head