both daily calibration checks and scheduled external calibration by certified agencies.

3. Responsibilities

• QC Chemist: Perform daily internal calibration checks and document results.
• QC Executive: Review calibration records and report any deviations.
• External Calibration Vendor: Carry out certified calibration as per annual schedule.

4. Accountability

The Head – QC is accountable for ensuring that all balances are calibrated as per defined schedules and are suitable for analytical use.

5. Procedure

5.1 Internal (Daily) Calibration

1. Use certified calibration weights traceable to national standards (e.g., 10 mg, 50 mg, 100 mg, 200 mg, 500 mg, 1000 mg).
2. Ensure the balance is leveled and on vibration-free surface before use.
3. Check the zero reading of the balance before placing any weight.
4. Place each standard weight and record the displayed value.
5. Compare the result with the actual weight and calculate the deviation.
6. Deviation should be within ±0.2 mg for 1 mg readability and ±0.1% for higher weights.
7. Document the results in the Daily Balance Calibration Logbook (Annexure-1).

5.2 External Calibration

1. Performed semi-annually or annually by a government-approved or NABL-accredited external agency.
2. Ensure the calibration certificate includes:
   • Calibration date
   • Serial number of the balance
   • Calibration range and results
   • Uncertainty of measurement
   • Authorized signature
3. Attach calibration certificate in the balance file and update the Calibration Schedule Tracker.

5.3 Out-of-Tolerance Handling

1. If deviation exceeds acceptable limits:
   • Tag the balance as “Out of Service”
   • Stop using the balance for any weighing
   • Inform the QC Manager immediately
   • Initiate corrective action and impact assessment for results generated since last calibration

5.4 Precautions

1. Do not touch standard weights with bare hands; use forceps or gloves.
2. Store standard weights in their original containers when not in use.
3. Do not place samples directly on balance pan; use clean containers or weighing paper.
4. Clean the balance pan before and after use with a lint-free cloth.

6. Abbreviations

• SOP: Standard Operating Procedure
• QC: Quality Control
• NABL: National Accreditation Board for Testing and Calibration Laboratories
• OOS: Out of Specification

7. Documents

1. Daily Balance Calibration Logbook (Annexure-1)
2. External Calibration Certificate
3. Calibration Schedule Tracker

8. References

• USP <41> – Weights and Balances
• 21 CFR Part 211 – US FDA GMP
• ICH Q7 – GMP for APIs
• ISO/IEC 17025 – General requirements for 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 Balance Calibration Logbook

Date	Balance ID	Weight Used	Displayed Value	Deviation	Result (Pass/Fail)	Checked By
13/04/2025	QC-BAL-03	100 mg	100.2 mg	+0.2 mg	Pass	Sunita Reddy

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
01/01/2022	1.0	Initial Issue	New SOP	QA Head
13/04/2025	2.0	Included out-of-tolerance and precautions section	Audit Compliance	QA Head