Practical 3(3) : Uniformity Of Weight Of Tablets And Capsules

OBJECTIVE

To study the uniformity of weight of tablets and capsules.
                
INTRODUCTION

The content uniformity test is used to ensure that every tablet contains the amount of drug substance intended with little variation among tablets within a batch. Due to increased awareness of physiological availability, the content uniformity test has been included in the monographs of all coated and uncoated tablets and all capsule intended for oral administration where the range of size of the dosage form available include 50mg or smaller sizes.


METHOD

Apparatus : weighing balance

Materials : 500g Paracetamol tablets (20 tablets) , 250g  mefenemic acid capsules (20 capsules)

A) Tablet

Procedures

1. 20 tablets were weighted previously selected at random. The average weight was determined.
2. Tablets were weighted individually and each tablets determined the percentage deviation of its weight from the average weight.
3. The deviation of individual weight from the average weight should not exceed the limits given below.

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



B) Capsule

1. 20 capsule were selected at random.
2. One capsule opened and the content removed as complete as possible. The emptied shells weighted. The net weight of its content, that is by substracting the weight of the shells from the weight of the intact capsule determined.
3. The procedure repeated with other 19 capsule.
4. The average net weight from the sum of the individual net weight was determined.
5. The percentage deviation was determined from the average net weight for each capsule. The deviation of individual net weight should not exceed the limits given below.

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



RESULT

A) Tablets

Weight of 20 tablet : 13.5920 g
Average of 20 tablet : 0.6796 g

Tablet
Weight of tablet (mg)
Deviation (±%)
1
4.7
0.69
2
4.3
0.63
3
5.2
0.77
4
21.3
3.13
5
3.2
0.47
6
10.6
1.56
7
8.0
1.18
8
1.0
0.15
9
11.9
1.75
10
2.8
0.41
11
4.4
0.65
12
5.7
0.84
13
3.7
0.54
14
6.4
0.94
15
2.1
0.31
16
6.2
0.91
17
2.7
0.40
18
1.0
0.15
19
17.3
2.55
20
4.1
0.60

B) Capsules

Average of 20 capsules: 0.3882 g

Capsule
Differences of powder between each capsule with the average 20 capsule (g)
Deviation (±%)
1
0.0177
4.56
2
0.0264
6.80
3
0.0004
0.10
4
0.0051
1.31
5
0.0048
1.24
6
0.0078
2.00
7
0.0067
1.73
8
0.0098
2.52
9
0.0049
1.26
10
0.0036
0.93
11
0.0103
2.65
12
0.0099
2.55
13
0.0091
2.34
14
0.0024
0.62
15
0.0045
1.16
16
0.0072
1.85
17
0.0033
0.85
18
0.0030
0.77
19
0.0012
0.31
20
0.0090
2.32



DISCUSSION

        This experiment was conducted to study the uniformity of weight of tablets and capsules. In this experiment, we use the 500mg Paracetamol tablets and 250g  mefenemic acid capsules to identify their uniformity of weight.

The percentage deviation (%) of tablets from the average weight of tablets can be calculated by this formula :

(weight of individual tablet -average weight of tablet) x 100%
                        Average weight of tablet

Whereas, for the calculation of deviation (%) of capsule, this formula was used :

(net content of capsule-average net content of capsule) x 100%
                        Average net content of capsule

         In the experiment, since the average mass obtained for 20 tablets is 0.6796 g which is greater than 250mg, thus minimum 18 tablets should not deviate from 0.6796 g by ±5%. The uniformity of weight of tablets is considered acceptable, because all 20 tablets fall within the range percentage of deviation which is from 0.15% to 3.13% (does not exceed 5%).

         For capsule, the average mass obtained is 0.3882 g that is more than 300mg, thus minimum 18 capsules must not deviate from average mass by ± 7.5%. Since all the 20 capsules fall within the range percentage of deviation from 0.01% to 6.80% which does not exceed 7.5%, thus the uniformity of weight of the capsules considered acceptable too. We assume that the concentration of drug, which is the weight of drug in each of the dosage form, is uniform.

         This experiment may not be accurate as well as there is some powder remained in the capsule when we carried out the uniformity test for capsule. Thus, we should take precaution by removing all powder from capsules during the test to make sure accuracy of result.

CONCLUSION

The 500mg Paracetamol and 250g mefenemic acid capsules follow the standard of uniformity of weight as there are minimum 18 tablets or capsules within the acceptable deviation. The paracetamol tablet and mefenamic acid capsules have uniform weight of contents in each dosage form.

REFERENCE



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