Standard Operating Procedure for Calibration of Balances Used for Dispensing in API Manufacturing

Department	API Manufacturing
SOP No.	SOP/API/020/2025
Supersedes	SOP/API/020/2022
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 routine calibration of balances used for weighing and dispensing raw materials to ensure consistent performance, accuracy, and compliance with GMP standards.

2. Scope

This SOP applies to all analytical and platform balances located in dispensing rooms, sampling booths, and raw material storage areas within the API manufacturing facility.

3. Responsibilities

• Warehouse Staff: Perform daily verification checks and record results.
• Engineering/Maintenance Team: Conduct internal monthly calibrations and coordinate external calibrations.
• QA Officer: Review calibration records and approve balances for continued use.

4. Accountability

The Engineering Manager is accountable for balance calibration execution, and the QA Manager is responsible for verification and compliance oversight.

5. Procedure

5.1 Balance Types and Identification

1. All balances must have:
   • Unique ID tag (e.g., BAL-001)
   • Calibration due date label
   • Daily verification record sheet
2. Types of balances:
   • Analytical Balance (readability: 0.1 mg or 1 mg)
   • Precision Balance
   • Platform Balance

5.2 Daily Verification

1. Use certified internal weights (Class E2 or F1) for daily verification.
2. Weigh standard weights (e.g., 1g, 10g, 100g) and record observations in the “Daily Verification Log” (Annexure-1).
3. Acceptable limits:
   • ±0.1% for analytical balances
   • ±0.5% for platform balances
4. Affix “Under Maintenance” label if deviation observed and inform engineering.

5.3 Monthly Calibration

1. Engineering performs calibration on or before the scheduled date using external certified weights.
2. Document results in the “Balance Calibration Record” (Annexure-2).
3. Recalibration must include:
   • Zero Check
   • Span Check (minimum to maximum range)
   • Linearity Check (multiple weight points)

5.4 Annual Calibration

1. External calibration agency (NABL accredited) performs annual calibration.
2. Calibration certificate to be archived and linked with balance ID (Annexure-3).
3. Maintain external calibration traceability records and ensure certificate is valid.

5.5 Calibration Failure Management

1. In case of calibration failure:
   • Immediately label the balance as “Out of Service.”
   • Initiate deviation and investigation report.
   • Quarantine materials weighed on the balance since last successful calibration.
2. Perform re-calibration or service before balance is returned to use.

6. Abbreviations

• SOP: Standard Operating Procedure
• QA: Quality Assurance
• NABL: National Accreditation Board for Testing and Calibration Laboratories
• GMP: Good Manufacturing Practice

7. Documents

1. Daily Verification Log (Annexure-1)
2. Balance Calibration Record (Annexure-2)
3. External Calibration Certificate Log (Annexure-3)

8. References

• ICH Q7 – GMP for Active Pharmaceutical Ingredients
• 21 CFR Part 211.68 – Calibration of automatic, mechanical, and electronic equipment
• ISO/IEC 17025 – General requirements for the competence of testing and calibration laboratories

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Daily Verification Log

Date	Balance ID	Weight Used	Observed Value	Status	Checked By
13/04/2025	BAL-001	100 g	100.01 g	Pass

Annexure-2: Balance Calibration Record

Calibration Date	Balance ID	Weight Range	Linearity Check	Status	Performed By
01/04/2025	BAL-001	0–2000 g	Pass	Pass

Annexure-3: External Calibration Certificate Log

Date	Balance ID	Agency	Certificate No.	Next Due Date
02/01/2025	BAL-001	Metrologix Labs	CAL-2025-101	02/01/2026

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
01/01/2022	1.0	Initial Issue	New Equipment SOP	QA Head
13/04/2025	2.0	Included External Calibration Requirements	Audit Enhancement	QA Head