The tablet friability test is one of the most important tests performed for uncoated tablets in the pharmaceutical industry by using an apparatus known as the Roch friabilator.

If you want to learn details about the Roch friabilator then read the following article because in the current article, we will only discuss the formula used for the probability calculation or how we calculate tablet Friability.

**Friability Formula **

To calculate the friability of uncoated tablets we use the following formula,

**W1-W2 ÷ W1 × 100**

W1 is the initial weight of the tablets meaning the weight of tablets before the friability test is known as W1.

W2 is the weight of tablets after the friability.

**How to calculate tablet Friability**

Take the required number of uncoated tablets as per pharmacopoeial specifications.

Clean the tablets means remove powder particles attached to the outer surface of tablets with the help of a small brush.

Check the weight of these tablets on a calibrated analytical weighing balance and note it.

This weight is known as W2 which we mentioned in the above formula.

Now open the lid of the friabilator and add the tablets into the friabilator and close the lid to run it for 4 minutes.

It will stop after completing 100 rpms in 4 minutes. Now remove the tablets out and physically inspect the tablets.

If there is any broken tablet in it then the test is considered failed and if no broken tablet is observed then clean the tablets again to remove any adhered powder particles and check the weight again.It will be W2.

Suppose that our initial weight was 7.25 gm (W1) and the final weight is 7.1 gm (W2).

Calculate the friability by adding the values in the formula.

**W1- W2 ÷ W1 × 100**

7.50 – 7.48 ÷ 7.50 × 100

=0.27 %

The friability value is 0.27 % and the acceptance criteria is not more than 1%. As our result lies within specifications, the test is considered pass.

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