Calibration is fundamental to maintaining the accuracy and reliability of tablet hardness testers in pharmaceutical quality control.
Why Calibration Matters
Measurement Accuracy
Regular calibration ensures the load cell and measurement systems provide accurate readings, preventing:
- False pass results for weak tablets
- Unnecessary rejections of good tablets
- Inconsistent quality data
Regulatory Compliance
Calibration is required for:
- GMP compliance
- Regulatory inspections
- Quality system certifications
Product Quality
Accurate hardness data ensures:
- Consistent product performance
- Proper disintegration and dissolution
- Patient safety
Calibration Components
Load Cell Verification
- Test against certified reference weights
- Verify linearity across measurement range
- Check for drift or hysteresis
Dimensional Measurements
For testers with thickness/diameter functions:
- Calibrate using gauge blocks
- Verify accuracy at multiple points
- Check for wear on measuring surfaces
Display and Recording
- Verify displayed values match standards
- Check data recording accuracy
- Validate software calculations
Calibration Frequency
Recommended Schedule
- Daily: Zero verification before use
- Weekly: Quick accuracy check
- Quarterly: Full calibration verification
- Annually: Complete calibration with certification
Trigger Events
Recalibrate after:
- Equipment repair or maintenance
- Physical impact or damage
- Relocation of equipment
- Suspect readings or OOS results
Documentation Requirements
Maintain records of:
- Calibration procedures used
- Reference standards with traceability
- Results before and after adjustment
- Technician identification
- Next calibration due date