Friability is defined as the % weight loss of powder from the surface of the tablets due to a mechanical process and the test is performed to measure the weight loss during transportation or movement of Tablets.
It’s a crucial test that’s carried out throughout the tablet’s production to verify that it won’t break or chip during coating, packaging, or normal handling during distribution to the patient. It is an additional test for Uncoated / Compressed Tablets other than physical measurements like Hardness (Tablet Breaking Force).
Because some formulations, when compressed into particularly hard tablets, tend to ‘cap’ or lose their crown parts on attrition, measuring the hardness of a tablet is not a good predictor of tablet strength. Such tablets are prone to powdering, chipping, and fragmentation.
In the friability test, the tablets are prone to abrasion, allowing us to assess tablet strength under various force applications.
USP Standards for Friability Test Apparatus:
| Sr. No. | Title | Specification |
| 1 | MOC (Materials of Construction ) and Property of Drum | Transparent Synthetic Polymer with polished internal surfaces. Develops minimum Static charge. One side is removable. |
| 2 | Drum attachment | Horizontal to the axis of the Instrument |
| 3 | Internal Diameter | 283.0 to 291.0 mm (287.0 ± 4.0 mm) |
| 4 | Depth | 36.0 to 40.0 mm (38.0 ± 2.0 mm) |
| 5 | Outer Diameter of Central Ring | 24.5 to 25.5 mm (25.0 ± 0.5 mm) |
| 6 | Curved Projection with inside Radius (Extends from middle to outer wall of drum) | 75.5 – 85.5 mm (80.5 ± 5.0 mm) |
| 7 | Drum Revolution/Minute | 24 – 26 (25 ± 1) |
| 8 | Drop Height | 154.0 – 158.0 mm (156.0 ± 2.0 mm) |
| 9 | Total Revolution / Test | 100 Revolutions / 4 Min. |
| 10 | Function | At each turn, the Tablets roll or slide and fall onto the drum wall or onto each other |
Precaution: Always do proper dedusting of tablets before and after the test to avoid an error.
Calculation:
Friability (%) = (W1 – W2)/ (W1) X 100
Where,
W1 = Weight of Tablets (Initial / Before Tumbling) &
W2 = Weight of Tablets (After Tumbling or friability)
Calibration of Friability Test Apparatus: Click Here
Read More:
Reference:
USP <1216>, EP<2.9.7>, and other pharmacopeias.
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