friability

Friability is the tendency of a material to crumble, break, or split into smaller pieces under mechanical stress or handling. The term is used across disciplines to describe a material's mechanical integrity, and it is influenced by microstructure, moisture, particle size, and cohesion. In geology and soil science, friable describes rocks and soils that break apart easily under pressure or moisture, such as chalk or certain shales; friable materials often have low strength and are prone to erosion or transport by wind or water.

In pharmaceutical manufacturing, friability is a quality attribute of dosage forms, especially tablets, indicating resistance to abrasion during packaging and transport. A friability test (Roche-type) subjects tablets to rotation in a drum, causing them to tumble and rub together; after a standardized cycle, the sample is weighed again and percent weight loss is reported. Acceptance criteria typically require a friability loss of 1% or less. Factors that increase friability include high moisture content, inadequate binding, poor compaction, and high porosity; measures to reduce friability include optimizing binders, compression force, and moisture control.

Friability is also used in pathology and clinical medicine to describe tissue that bleeds easily when manipulated; friable mucosa or lesions are characteristic of inflammation, infection, or neoplastic processes and can indicate fragility during biopsy or examination.