How to Calibrate Tablet Friability Testers and Key Parameters

Proper calibration of tablet friability testers ensures accurate assessment of tablet mechanical strength according to pharmacopeial requirements.

Key Calibration Parameters

Rotation Speed

The drum must rotate at a fixed speed of 25 ± 1 rpm:

• Use a calibrated tachometer to measure speed
• If speed deviates, adjust motor controller
• Verify at beginning and during rotation cycle

Fall Height

The tablets must fall from a consistent height:

• Measured using a scale or gauge
• Must align with 6.3 ± 0.2 mm standard
• Check drum interior for wear or damage

Rotation Count

Standard test requires exactly 100 rotations:

• Verify counter accuracy
• Test timer correlation (4 minutes at 25 rpm)
• Check for consistent counting

Drum Condition

Inspect drum for:

• Cracks or chips
• Internal surface smoothness
• Proper mounting and balance

Calibration Procedure

1. Visual Inspection: Check drum and drive system
2. Speed Verification: Measure rotation speed with tachometer
3. Count Verification: Confirm accurate rotation counting
4. Height Check: Verify fall height specification
5. Timer Verification: Compare to calibrated stopwatch
6. Documentation: Record all measurements

Acceptance Criteria

Per USP <1216>:

• Rotation speed: 25 ± 1 rpm
• Test duration: 100 rotations
• Weight loss limit: Typically <1%

Maintenance

• Keep drum clean and free of tablet residue
• Check drive belt tension regularly
• Verify interlock safety systems
• Clean and inspect regularly