documented in calibration logs and tracked using a central register or CMMS software like those featured on PharmaGMP.in.

Analytical Balance Calibration Procedure

1. Warm-Up: Switch on the balance and allow at least 30 minutes for stabilization.
2. Zero Check: Ensure the display reads “0.0000” before beginning.
3. Internal Check (if applicable): Use built-in calibration function if present.
4. External Calibration:
   • Use certified weights (e.g., Class E2 or F1)
   • Place 5 g, 10 g, 20 g, and 50 g weights and record readings
   • Acceptance Criteria: ±0.2 mg for 5–20 g; ±0.4 mg for 50 g
5. Repeatability Test: Weigh 10 g five times. Calculate %RSD.
   • Acceptance: RSD ≤ 0.1%

Sample Data Table: Balance Linearity and Accuracy

Nominal Weight	Observed Value	Deviation (mg)	Status
5.0000 g	5.0002 g	+0.2	PASS
10.0000 g	10.0001 g	+0.1	PASS
20.0000 g	19.9998 g	-0.2	PASS
50.0000 g	50.0005 g	+0.5	FAIL*

*Fails limit of ±0.4 mg. Requires adjustment and repeat calibration.

Reference Weight Calibration

Certified weights must be traceable to national standards (e.g., NIST, NABL). Calibration must be done every 1–2 years based on usage and audit risk profile.

Calibration certificate must include:

• Weight Class (E2, F1, etc.)
• Nominal Value
• Actual Value & Uncertainty
• Date of Calibration and Next Due Date
• Traceability Chain

Store weights in anti-static, clean containers. Avoid direct contact to minimize contamination and ensure consistent readings.

Pipette and Volumetric Glassware Calibration

Pipettes and volumetric flasks are vital for solution preparation and microbial assays. Their calibration must follow gravimetric methods, especially for small volumes (≤10 mL).

Gravimetric Method for Pipette Calibration:

1. Weigh a tared container on a calibrated analytical balance.
2. Dispense set volume (e.g., 1.000 mL) of deionized water at 20°C.
3. Weigh again and calculate the delivered volume using water density (0.9982 g/mL at 20°C).
4. Repeat 10 times and calculate the mean, %RSD, and deviation.

Acceptance Criteria:

• Accuracy: ±1% of target volume
• Precision (RSD): ≤0.5%

Volumetric Flask Calibration (Volumetric Method):

• Fill flask with purified water to calibration mark.
• Weigh the full flask and empty flask separately.
• Calculate the delivered volume using water density.
• Compare with nominal volume and calculate % deviation.

Use calibrated thermometer to ensure temperature correction is applied.

Deviation and Out-of-Tolerance Handling

When calibration results fall outside limits:

• Tag equipment as “Out of Calibration – Do Not Use”.
• Initiate deviation with full impact assessment.
• Review past data generated using the device since last acceptable calibration.
• Recalibrate or replace equipment before resuming use.
• Document CAPA and retrain if root cause is linked to human error.

Refer to deviation SOP templates at PharmaSOP.in for standardized approach.

Calibration Schedule and Register

Maintain a master calibration register with:

• Equipment ID
• Last Calibration Date
• Next Due Date
• Status (Pass/Fail)
• Calibrated By / Verified By

Use of LIMS or spreadsheet trackers with auto-reminders is recommended. Include validation reference in CMP or Quality Plan.

GMP Compliance and Audit Expectations

During inspections, regulators expect clear traceability from equipment use to calibration documentation. Key focus areas include:

• Availability of valid calibration certificates
• Timely execution and review of calibration
• OOT handling and historical data reviews
• Qualification linkage (DQ, IQ, OQ, PQ)
• ALCOA+ adherence in calibration records

Training and Qualification of Calibrators

Only trained personnel must perform calibration. Training should include:

• Use of reference standards
• Environmental condition controls (temperature, humidity)
• GMP documentation practices
• Deviation and CAPA process

Requalification frequency: annually or post any calibration failure or audit observation.

Sample Calibration Protocol Format

Ensure every calibration is preceded by an approved protocol containing:

• Objective and scope
• Responsibility
• Calibration steps and test plan
• Acceptance criteria
• Data capture sheet
• Deviation handling steps
• Approval section (QA/Engineering)

Integration with Equipment Lifecycle

Calibration is linked to equipment qualification stages:

• IQ: Verify device supports calibration features
• OQ: Confirm calibration performs under range of intended use
• PQ: Ensure device maintains calibration during routine operation

Include calibration validation in StabilityStudies.in and related method transfer or assay validation plans.

Conclusion

Robust calibration protocols for weighing and volume equipment are essential for pharma data integrity and regulatory success. With the correct reference standards, validated procedures, and proper documentation, labs can ensure high precision, traceability, and audit-readiness.

Explore downloadable calibration logs, printable deviation forms, and equipment SOPs at PharmaSOP.in and pharmaregulatory.in.