Uniformity of weight of tablets and capsules

Title

Uniformity of weight of tablets and capsules

Aim

To determine the uniformity of weight of tablets and capsules

Materials and apparatus

Weighing boat

20 capsules

20 tablets

Weighing balance

Spatula

Introduction

To ensure the consistency of dosage units, each unit in a batch should have a drug substance content within a narrow range around the label claim. Dosage units are defined as dosage forms containing a single dose or a part of a dose of drug substance in each unit. The uniformity of dosage units specification is not intended to apply to suspensions, emulsions, or gels in unit-dose containers intended for topical administration. The term “uniformity of dosage unit” is defined as the degree of uniformity in the amount of the drug substance among dosage units. Therefore, the requirements of this chapter apply to each drug substance being comprised in dosage units containing one or more drug substances, unless otherwise specified in the individual monograph. The uniformity of dosage units can be demonstrated by either of two methods, Content Uniformity or Weight Variation.

Procedure

Tablets

1. 20 tablets previously selected at random were weighed and the average weight was determined.

2. All of the tablets were weighed individually and each tablet was determined for  the percentage deviation of it’s weight from the average weight.

3. The deviation of individual weight from the average weight shall not exceed the limits given below.

Average weight of tablet	Deviation (%)	Number of tablets
Less than 80 mg.	± 10.0	Minimum 18
	± 20.0	Maximum 2
80 mg to 250 mg	± 7.5	Minimum 18
	± 15.0	Maximum 2
More than 250 mg.	± 5.0	Minimum 18
	± 10.0	Maximum 2

Capsule

1. 20 capsules were selected at random.

2. One capsule was weighed. The open capsule was opened and the contents were removed as completely as possible. The emptied shells then were weighed. After that, the net weight of its contents was determined by subtracting the weight of the shells from the weight of the intact capsule.

3. The procedure was repeated with other 19 capsules.

4. The average net weight from the sum of the individual net weights were determined.

5. The percentage deviation from the average net weight for each capsule was determined. The deviation of individual net weight shall not exceed the limits given below:

Average net weight of capsule	Deviation (%)	Number of tablets
Less than 300 mg.	± 10.0	Minimum 18
	± 20.0	Maximum 2
300 mg or more	± 7.5	Minimum 18
	± 15.0	Maximum 2

Results 

For tablets

Average weight: total weight/20

                             = 7.0445/20

                             = 0.35224

Deviation: (weight of one tablet – average weight / average weight) x 100 %

                     

Weight of tablets	Deviation %
0.3552	0.84
0.3563	1.15
0.3528	0.159
0.3486	1.0330
0.3521	0.04
0.3515	0.1988
0.3534	0.329
0.3506	0.4656
0.3523	0.0170
0.3492	0.8630
0.3530	0.2271
0.3531	0.2555
0.3528	0.1704
0.3532	0.2839
0.3530	0.2271
0.3515	0.1988
0.3512	0.2839
0.3508	0.3975
0.3523	0.0284

Capsules

Average weight of capsule: total weight of capsule with contents- total weight without content/ 20

                                                = 9.2455 – 1.5392 / 20

                                                = 0.3853

Deviation %: { (weight of capsule with contents – weight without contents)-average     weight/average weight } x 100 %

Weight of capsule with contents / g	Weight of capsule without contents/g	Deviation / %
0.4689	0.0760	1.972
0.4732	0.0748	3.400
0.4717	0.0777	2.258
0.4762	0.0808	2.621
0.4693	0.0802	7.994
0.4488	0.0746	2.880
0.4726	0.0796	1.998
0.4521	0.0785	3.037
0.4672	0.0816	0.0779
0.4517	0.0727	1.635
0.4652	0.0775	0.623
0.4644	0.0803	0.311
0.4740	0.0762	3.244
0.4480	0.0804	4.594
0.4634	0.0765	0.4153
0.4652	0.0753	1.1939
0.4562	0.0761	1.350
0.4417	0.0736	4.46
0.4617	0.0736	0.727
0.4540	0.0732	1.168

Discussion

The Test of Uniformity was carried out by using tablets and capsules. They are being tested in order to ensure the accurate and consistency of the drugs when administered in the body. Unfortunately, this test of uniformity is not applicable to tablets and capsules required to comply with test for uniformity of contents because the drug substances present in lesser proportion is demonstrated by content variation.

While conducting this experiment, the average mass obtained for 20 tablets is 0.325g which is greater than 250mg .The minimum required for 18 tablets should not deviate from 0.325g by ±  5%. The uniformity of weight tablets is acceptable as long as all 20 tablets fall within the range limit mass (0.3525g to 0.3701g)

For capsule, the average mass obtained is 385, 3 g which is more than 350 mg, therefore minimum 18 capsules should not deviate from average mass by  ± 10 %.  The uniformity of the capsule is acceptable as long as all 20 capsules are all fall within the range limit less than the percentage deviation stated. We assume the concentration of drug which is the weight of drug per weight of dosage form is uniform.

However, the results might not accurate since human occur can always occur. For example when transferring the component or reaction to another container, we will lose some of the compound. Therefore this will lead the yield to be lesser than 100%. Therefore, the shell of capsule should be completely emptied before weight. Plus, the weighing balance should be calibrated first before experiment is conducted.

Question

3. Give reasons for the non-compliance to test for uniformity of weight

It takes a longer period to weigh the tablets and capsules one by one. For capsules, it is consuming a lot of time to open out the coated shell just to weigh the capsule with  and without the contents.

Conclusion

All tablets and capsules are successfully followed the standard of uniformity of weight since not more than 2 of the individual masses deviate from the average mass by more than the percentage deviation stated. The objective of the experiment is successfully achieved.

References

1.      https://www.google.com/search?q=non+compliance