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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