Weigh 20 suppositories individually and calculate the average mass. When the suppositories are weighed singly, the deviation of individual mass from the average mass should not exceed the limits as indicated in Table 7.4.

Table 7.4 Deviation of Individual Mass of Suppositories from Average Mass

Not more than two of the individual masses should deviate from the average mass by more than 5% and none deviates by more than 10%.

Procedure: The steps for determining the uniformity of mass are as follows:

1. Weigh 20 suppositories individually (w₁, w₂, w₃, …, w₂₀).
2. Weigh all the suppositories together (W).
3. Calculate the average weight (W/20).
4. Limit: Not more than two suppositories differ from the average weight by more than 5%, and no suppository differs from the average weight by more than 10%. Not more than two of the suppositories differ from the average weight by more than the error percentage listed. If more than two suppositories are different from the average weight by 5%, calculate double the percentage error as follows: