Experiment 3: Uniformity of weight of tablets and capsules

Title

Uniformity of weight of tablets and capsules

Objective

To study whether the uniformity of weight of tablets and capsules comply with the standard of British Pharmacopoeia or not.

Date of Experiment

4th December 2014

Introduction

Uniformity of weight of tablets and capsules is an important quality assessment to ensure that each of the tablet and capsule produced meets the requirement of pharmacopoeia standard and also manufacturing standard. Uniformity of weight test is not applicable to tablets and capsules required to comply with the test for uniformity of content. 

Uniformity of tablets and capsules ensure that patient will get accurate dose of drug in tablet or capsule form to prevent the toxic effect or getting no therapeutic effect. Therefore, uniformity test of weigh of tablets and capsules is carried out in manufacturing process to make sure those produced tablets and capsules fit the requirements.

Apparatus

Weighing balance, weighing boat

Materials

20 tablets, 20 capsules

Procedures

Tablets:

1)      20 tablets previously selected at random were weighed. The average weight was determined.

2)      The tablets were weighed individually and for each tablet, the percentage deviation of its weight from the average weight was determined.

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

Average weight of tablet	Deviation (%)	Number of tablets
<80 mg	±10.0 ±20.0	Minimum 18 Maximum 2
80-250 mg	±7.5 ±15.0	Minimum 18 Maximum 2
>250 mg	±5.0 ±10.0	Minimum 18 Maximum 2

Capsules:

1)      20 capsules were selected at random.

2)     One capsule was weighed. The capsule was opened and the contents were removed as completely as possible. The emptied shells were then weighed. The net weight of its content 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 was determined from the sum of the individual net weights.

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

Average net weight of capsule	Deviation (%)	Number of capsules
<300 mg	±10.0 ±20.0	Minimum 18 Maximum 2
≥300 mg	±7.5 ±15.0	Minimum 18 Maximum 2

Results

20 Tablets:

Tablet	Individual weight(g)	Difference between individual weight and average weight (g)	Percentage of deviation(%)
1	0.6536	0.0037	0.56
2	0.6721	0.0148	2.25
3	0.6789	0.0036	3.29
4	0.6586	0.0013	0.20
5	0.6591	0.0018	0.27
6	0.6490	0.0083	1.26
7	0.6674	0.0101	1.54
8	0.6607	0.0034	0.52
9	0.6492	0.0081	1.23
10	0.6549	0.0024	0.37
11	0.6522	0.0051	0.78
12	0.6641	0.0068	1.03
13	0.6629	0.0056	0.85
14	0.6566	0.0007	0.11
15	0.6661	0.0088	1.34
16	0.6645	0.0072	1.10
17	0.6540	0.0033	0.50
18	0.6656	0.0083	1.26
19	0.6651	0.0078	1.19
20	0.6558	0.0015	0.23

i.                    Average weight =   13.146g  =  0.6573g

                                                  20

ii.                  Since the average weight  is 657.3mg which is more than 250mg, so the deviation                are ±5% and ±10% ,

a.                  % deviation ±5%    =  95% ≤ X ≤ 105%  = 624.44 mg ≤ X ≤ 690.17 mg

                                             

b.                 % deviation ±10%  =  90% ≤ X ≤ 110% = 591.57 mg ≤ X ≤ 723.03 mg

                                             

iii.                No tablets deviate from the weight so this product passed the uniformity of weight                 test.

 20 Capsules:

Capsules	Individual weight(g)	Difference between individual weight and average weight (g)	Percentage of deviation(%)
1	0.3944	0.0028	0.72
2	0.3951	0.0035	0.89
3	0.3869	0.0047	1.20
4	0.3873	0.0043	1.10
5	0.3934	0.0018	0.46
6	0.3797	0.0119	3.04
7	0.3951	0.0035	0.89
8	0.4005	0.0089	2.27
9	0.3759	0.0157	4.01
10	0.3922	0.0006	0.15
11	0.3956	0.0040	1.02
12	0.3972	0.0056	1.43
13	0.3972	0.0056	1.43
14	0.3859	0.0057	1.46
15	0.3829	0.0087	2.22
16	0.4018	0.0102	2.61
17	0.4016	0.0100	2.55
18	0.3802	0.0114	2.91
19	0.3926	0.0010	0.26
20	0.3960	0.0044	1.12

  

i.                    Average weight =   7.8315g  =  0.3916g

                                                  20

ii.                  Since the average weight  is 391.6mg which is more than 300mg, so the deviation                are ±7.5% and ±15.0% ,

a.                  % deviation ±7.5%    =  92.5% ≤ X ≤ 107.5%  = 362.23 mg ≤ X ≤ 420.97 mg

                                             

b.                 % deviation ±15.0%  =  85.0% ≤ X ≤ 115.0% = 332.86 mg ≤ X ≤ 450.34 mg

                                             

iii.                No capsules deviate from the weight so this product passed the uniformity of                          weight test.

Discussion

            According to the results obtained, the average weight of the tablet Ettroccin 250 is 0.6573g (657.3mg) which means the range of more than 250 mg is the suitable range chose from the table of the deviation limits. From the data obtained, it is found that all tablets follow the limits. This shows that all tablets tested in this experiment are uniform in the aspect of weight.

          The average weight of the NSAID capsules  is 0.3916 g (391.6 mg) which are more

 than 300mg. Therefore, the deviation limits follow the limits for the range of 300 mg or more. Thus, all capsules tested are also uniform in weight.

          The errors might arise when measuring the weight of these tablets and capsules. The poor powder flowability causes some powders might still get stuck inside the capsule shells. As the powders are not completely removed, the measurements of emptied shells are not accurate. Furthermore, errors might also due to the air flow or wind around the weighing balance to influence the reading of weighing balance. All these errors will lead to inaccuracies of measurement of weight.

Conclusion

The uniformity of weight of tablets and capsules test is useful in quality control during the production of tablets and capsules. In this experiment, it is found that all tablets and capsules used are uniform.

References

1. Florence E. Eichie, Ikhuoria M. Arhewoh and Oliver C. Ezeobi, 13 August 2009. In- vitro evaluation of the pharmaceutical quality of some ibuprofen tablets dispensed in Nigeria.

2. African Journal of Pharmacy and Pharmacology Vol. 3 (10).

3. http://www.academicjournals.org/ajpp