Title: Determination of uniformity weight
1. Objective: Determination of uniformity weight tablets, capsules and powders as per IP.
2. Principle: The test for uniformity of weight of single-dose preparations is based on the individual single-dose units to determine whether the individual unit weight are within limits set with reference to the average content of the sample.
3. Procedure:
3.1 Uniformity weight tablets, capsules and powders:
Weigh individually 20 units selected at random or, for single dose preparations in individual containers, the contents of 20 units, and calculate the average weight. Not more than two of the individual weights deviate from the average weight by more than the percentage shown in the table and none deviates by more than twice that percentage.
| Dosage
form |
Average weight | Percentage deviation | Number of tablets |
| Uncoated
and film coated tablets
|
80 mg or less | ± 10 | 18 |
| ± 20 | 2 | ||
| More than 80 mg but less than 250 mg | ± 7.5 | 8 | |
| ± 15 | 2 | ||
| 250 mg or more | ± 5 | 18 | |
| ± 10 | 2 | ||
| Capsules, granules and powders(single dose) | Less than 300 mg | ± 10 | 18 |
| ± 20 | 2 | ||
| 300 mg or more | ± 7.5 | 18 | |
| ± 15 | 2 |
| Dosage
form |
Average weight | Percentage deviation | Number of tablets |
| Powders for parenteral use | More than 40 mg | ± 10 | 18 |
| ± 20 | 2 |
For capsules
Weigh an intact capsule. Open it without losing any part of the shell and remove the contents as completely as possible. For soft gelatin capsules, wash the shell with a suitable solvent and keep aside until the odour of the solvent is not perceptible. Weigh the shell. The difference between the weighing gives the weight of the contents. Repeat the procedure with another 19 capsules.
For powders for parenteral use
Remove any adhering labels from a container and wash and dry the outside. Open the container and immediately weigh it along with the contents. Empty it as completely as possible by gentle tapping, rinse it with water and then with ethanol. Dry at 100°C to 105°C for one hour, or if the nature of the contents does not permit drying at this temperature, dry at a lower temperature to constant weight. Cool in a desiccator and weigh. The difference in the weighing gives the weight of the contents of the container. Repeat the procedure with another 19 containers.
Weight of 20 unit : X
Average weight : X/20 = Y
Y= should meet specified criteria