Following proper precautions during friability testing ensures accurate results and valid quality assessments.
Pre-Test Precautions
Sample Preparation
- Remove any loose dust from tablets before weighing
- Use calibrated analytical balance
- Handle tablets carefully to avoid pre-test damage
- Allow tablets to equilibrate to room conditions
Equipment Verification
- Check drum for cleanliness and damage
- Verify rotation speed before each batch
- Ensure proper drum mounting
- Confirm counter/timer accuracy
Weight Specifications
- Tablets weighing ≤650 mg: Test 20 tablets
- Tablets weighing >650 mg: Test 10 tablets
- Record initial weight to appropriate precision
During Test Precautions
Observation
- Monitor for any unusual drum behavior
- Watch for tablets becoming stuck
- Note if tablets break into pieces
Environment
- Maintain consistent room conditions
- Avoid vibrations near equipment
- Control dust and airflow
Post-Test Precautions
Sample Handling
- Remove tablets carefully from drum
- Use soft brush to remove loose dust
- Do not press or handle tablets excessively
Weighing
- Weigh tablets as a group (same as initial)
- Use same balance as initial weighing
- Record to appropriate decimal places
Result Calculation
Weight loss % = [(Initial Weight - Final Weight) / Initial Weight] × 100
Acceptance Criteria
- Maximum allowable weight loss: typically 1%
- If limit exceeded, may retest once
- Document all results including failures
Common Errors to Avoid
- Using damaged or chipped tablets
- Incomplete dust removal
- Incorrect rotation count
- Inconsistent weighing technique
- Improper documentation