Friability Testing – Friability of uncoated tablets

Friability (the condition of being Friable) testing is a methodology, used to see the physical strength of compressed and uncoated tablets upon exposure to mechanical shock and attrition. In simple words, what quantity of mechanical stress tablets will stand up to throughout their production, distribution, and handling process.

Friability Test Apparatus: Friability test apparatus consists of a drum of a transparent synthetic polymer with polished internal surfaces having minimum static charge. One facet of the drum is removable.

Dimensions: The Internal diameter of the drum is between 283 and 291 mm and a depth between 36 and 40 mm. The tablets fall down with each turn of the drum by a curved projection with an inside radius between 75.5 and 85.5 mm that extends from the middle of the drum to the outer wall. The outer diameter of the central ring is 24.5 mm to 25.5. The drum is attached to the horizontal axis of a device that rotates at 25 ±1 rpm

Test Method:

For tablets with a unit mass equal to or less than 650 mg, take a sample of whole tablets corresponding to 6.5 g. For tablets with a unit mass of more than 650 mg, take a sample of 10 whole tablets.

Dedust the tablet carefully and weigh accurately the tablet sample. Place the tablets in the drum. Rotate the drum 100 times with a speed of 25 rpm, remove the tablets, remove any loose dust from the tablets as before, and accurately weigh.

Calculation:

Friability (%)  = W1 – W2/ W1  X 100

Where,
W1 = Weight of Tablets (Initial / Before Tumbling) &
W2 = Weight of Tablets (After Tumbling or friability)

Limit : Friability (%) = Not More Than 1.0 %

Generally, the test is run once. If cracked, cleaved, or broken tablets are present in the tablet sample after tumbling, the sample fails the test. If the results are doubtful or if the weight loss is greater than the targeted value. The test should be repeated twice and the mean of the three tests should be calculated. A maximum mean weight loss from the three samples of not more than 1.0% is considered acceptable for most products.

If tablet size or shape causes irregular tumbling, the drum base should be adjusted, so that the base forms an angle of about 10° with the bench top and the tablets do not bind together when lying next to each other, which prevents them from falling freely.

An appropriate humidity­ controlled environment is required for testing of hygroscopic tablets.

Summary:

  • Friability is defined as the % of weight loss by tablets due to mechanical action during the test.
  • Rotate the drum 100 times with a speed of 25 rpm.
  • For tablets with a unit mass equal to or less than 650 mg, take a sample of whole tablets corresponding to 6.5 g.
  • For tablets with a unit mass of more than 650 mg, take a sample of 10 whole tablets.
  • Limit: Friability % : Not more than: 1.0%

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