UNIFORMITY OF WEIGHT OF TABLETS AND CAPSULES.

Objective:

To test the uniformity of weight of tablets and capsules whether it comply with the Pharmacopoeial standard or not.

Material and Apparatus:

Paralgin tablets, Ampillin capsules, weighing balance and weighing boats.

Method:

Tablets

1.       20 tablets are selected at random and weighed. The average weight is determined.

2.       Tablets are weighed individually and for each tablet, the percentage deviation of its weight from the average weight is determined.

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 80 mg.	± 10.0 ± 20.0	Minimum 18 Maximum 2
80 mg to 250 mg	± 7.5 ± 15.0	Minimum 18 Maximum 2
More than 250 mg.	± 5.0 ± 10.0	Minimum 18 Maximum 2

Capsules

1.       20 capsules are selected at random.

2.    A capsule is weighed. The capsule is opened and the contents are removed as completely as possible. The emptied shells are weighed. The net weight of its contents is determined, that is by subtracting the weight of the shells from the weight of the intact capsule.

3.    The proceduresare repeated with other 19 capsules.

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

5.    The percentage deviation from the average net weight for each capsule is determined.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

Results and Calculation:

Formula

Tablets

Tablets	Weight (g)	Deviation (%)
Total	13.6449
Average	0.6822
1	0.6856	0.50
2	0.6881	0.86
3	0.6805	-0.25
4	0.6846	0.35
5	0.6781	-0.60
6	0.6657	-2.42
7	0.6638	-2.70
8	0.6675	-2.15
9	0.6832	0.14
10	0.6890	0.99
11	0.6954	1.93
12	0.6972	2.20
13	0.7000	2.61
14	0.6751	-1.04
15	0.6839	0.25
16	0.6921	1.45
17	0.6727	-1.39
18	0.6625	-2.89
19	0.6905	1.22
20	0.6894	1.06

Capsules

Capsules	Weight (g)			Deviation (%)
	Whole	Cap	Net
1	0.3607	0.0583	0.3024	3.53
2	0.3590	0.0632	0.2958	1.27
3	0.3702	0.0652	0.3050	4.42
4	0.3515	0.0651	0.2864	-1.95
5	0.3609	0.0627	0.2982	2.09
6	0.3477	0.0649	0.2828	-3.18
7	0.3659	0.0635	0.3024	3.53
8	0.3590	0.0609	0.2981	2.05
9	0.3554	0.0625	0.2929	0.27
10	0.3593	0.0632	0.2961	1.37
11	0.3578	0.0633	0.2945	0.82
12	0.3385	0.0622	0.2763	-5.41
13	0.3342	0.0618	0.2724	-6.74
14	0.3540	0.0630	0.2910	-0.38
15	0.3439	0.0631	0.2808	-3.87
16	0.3495	0.0672	0.2823	-3.36
17	0.3632	0.0574	0.3058	-4.69
18	0.3522	0.0624	0.2898	-0.79
19	0.3520	0.0592	0.2928	0.24
20	0.3584	0.0613	0.2971	1.71
Total			5.8429
Average			0.2921

Discussion:

                The tablets used is Paralgin(paracetamol500 mg)with average weight of 682 mg therefore, we used this rule:

More than 250 mg.

± 5.0 ± 10.0

Minimum 18 Maximum 2

It seems that all 20 tablets tested did not exceed.The positive deviation means that the individual weight is more than the average weight and negative percent deviation indicates individual weight is less than average weight.

                The capsules used in experiment is Ampicillin trihydrate (Ampicillin BP 250 mg) with average weight of 292 mg therefore, we used this rule:

Less than 300 mg.

± 10.0 ± 20.0

Minimum 18 Maximum 2

It seems that no capsule deviate more than  %.

Conclusion:

                All tablets and capsules tested comply with pharmacopoeial standard of uniformity of weight.

Question

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

The non-compliance to test for uniformity of weight is due to:

a.       The decayed/expired/degeneration/decomposed ingredient of the drug.

b.      Uneven feeding of granules into the die due toirregular movement of the lower punch that cause variation in capacity die space.

c.       Packing geometry.

References:

Gresham HS.http://science.halleyhosting.com/sci/soph/inquiry/percentdev.htm. Percent Deviation.Student Watershed Research Project.Retrieved on23rd December 2013.