Granule friability testing is an important quality control measure in pharmaceutical manufacturing that evaluates the mechanical strength of granules before compression into tablets.
Why Granule Friability Matters
Granules that are too friable can cause:
- Excessive dust generation during processing
- Weight variation in finished tablets
- Content uniformity issues
- Equipment contamination
Testing Methodology
Granule friability is typically tested by:
- Weighing a specific quantity of granules
- Subjecting them to mechanical stress in a rotating drum
- Sieving to remove fines generated
- Calculating percentage weight loss
Factors Affecting Granule Friability
Granulation Process
- Binder concentration: Higher binder levels generally reduce friability
- Granulation time: Extended mixing can affect granule strength
- Drying parameters: Over-drying can increase friability
Moisture Content
The moisture content in granules should ideally be between 1 to 3% tested by Loss on Drying. Too much or too little moisture affects mechanical properties.
Particle Size Distribution
The ideal poured density of dried granules before compression should be between 0.55 to 0.65 gms per cubic cm.
Impact on Downstream Processing
Granulation quality directly influences:
- Tableting: Proper granule strength prevents capping and lamination
- Coating: Consistent granules ensure uniform coating application
- Packaging: Reduced dust improves packaging line efficiency
Quality Specifications
Acceptable friability limits vary by product but typically range from 0.5% to 1.0% weight loss for pharmaceutical granules.