UNIFORMITY OF WEIGHT OF TABLET AND CAPSULE

TITLE : Uniformity Of Weight Of Tablet And Capsule

OBJECTIVE :

1. to ensures consistency of dosage units during compression.

INTRODUCTION :
The term “uniformity of dosage unit” is defined as the degree of uniformity in the amount of the drug substance among dosage units. The uniformity of dosage unit specification is not intended to apply to suspensions, emulsions, or gels in unit-dose containers intended for topical administration. Therefore, the requirements of this chapter apply to each drug substance being comprised in dosage units containing one or more drug substances. Uniformity of weight is an in process test parameter which ensures consistency of dosage units during compression. Uniformity of weight is applicable capsules and tablets.  Tablet is a medicinal formulation made of a compressed powdered substance containing an active drug and excipients. Capsule is  a solid dosage form in which the drug is enclosed in a hard or soft soluble container, usually in a form of gelatin. This test is necessary to ensure that patients take a precise pharmaceutical dose. The reasons behind this practice include providing the patient with the desired dose. If the product is not available in the required strength, starting therapy with the lowest possible doses is needed to reduce the incidence of side effects of certain drugs.

EXPERIMENTAL METHOD:

Weighing balance, 20 tablets, 20 capsules

TABLETS

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

2.      Tablets was weighed individually and determined for each tablet

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 was selected at random

2.      One capsule was weighed. Capsule was opened and the content was removed as completely as possible. The emptied shell was weighed. The net weight of its content was determined that is by substracting 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

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 CALCULATIONS :

TABLET

Total weight of tablet = 13.2312 g

Average weight of tablet = 13.2312 g/20 tablet

                                 = 0.66156 g/tablet = 661.56 mg/tablet

Thus, the percentage deviation of individual weight from the average weight should not exceed the limits in the range of more than 250 mg.

NO.	MASS OF TABLET (mg)	CALCULATIONS	PERCENTAGE DEVIATION (%)
1	653.30	661.56 mg – 653.30 mg = 8.26 mg 8.26 mg/661.56 mg X 100% = 1.25%	1.25%
2	669.10	661.56 mg – 669.10 mg = -7.54 mg  -7.54 mg/661.56 mg X 100% = -1.14%	-1.14%
3	659.50	661.56 mg – 659.50 mg = 2.06 mg  2.06 mg/661.56 mg X 100% = 0.31%	0.31%
4	657.60	661.56 mg – 657.60 mg = 3.96 mg  3.96 mg/661.56 mg X 100% = 0.60%	0.60%
5	666.10	661.56 mg – 666.10 mg = -4.54 mg  -4.54 mg/661.56 mg X 100% = -0.69%	-0.69%
6	663.60	661.56 mg – 663.60 mg = -2.04 mg -2.04 mg/661.56 mg X 100% = 0.31%	0.31%
7	675.80	661.56 mg – 675.80 mg = -14.24 mg  -14.24 mg/661.56 mg X 100% = -2.15%	-2.15%
8	658.10	661.56 mg – 658.10 mg = 3.46 mg 3.46 mg/661.56 mg X 100% = 0.52%	0.52%
9	659.10	661.56 mg – 659.10 mg = 2.46 mg 2.46 mg/661.56 mg X 100% = 0.37%	0.37%
10	672.10	661.56 mg – 672.10 mg = -10.54 mg -10.54 mg/661.56 mg X 100% = -1.59%	-1.59%
11	640.40	661.56 mg – 640.40 mg = 21.16 mg 21.16 mg/661.56 mg X 100% = 3.20%	3.20%
12	659.60	661.56 mg – 659.60 mg = 1.96 mg 1.96 mg/661.56 mg X 100% = 0.30%	0.30%
13	652.80	661.56 mg – 652.80 mg = 8.76 mg 8.76 mg/661.56 mg X 100% = 1.32%	1.32%
14	657.50	661.56 mg – 657.50 mg = 4.06 mg 4.06 mg/661.56 mg X 100% = 0.61%	0.61%
15	667.90	661.56 mg – 667.90 mg = -6.34 mg -6.34 mg/661.56 mg X 100% = -0.96%	-0.96%
16	664.60	661.56 mg – 664.60 mg = -3.04 mg  -3.04 mg/661.56 mg X 100% = -0.46%	-0.46%
17	658.10	661.56 mg – 658.10 mg = 3.46 mg 3.46 mg/661.56 mg X 100% = 0.52%	0.52%
18	684.80	661.56 mg – 684.80 mg = -23.24 mg -23.24 mg/661.56 mg X 100% = -3.51%	-3.51%
19	652.60	661.56 mg – 652.60 mg = 8.96 mg 8.96 mg/661.56 mg X 100% = 1.35%	1.35%
20	658.00	661.56 mg – 658.00 mg = 3.56 mg 3.56 mg/661.56 mg X 100% = 0.54%	0.54%

CAPSULE

Mass of sum of powder capsule = 5953.2 mg

Average net weight = 5953.2 mg/ 20 capsule

                         = 297.66 mg/capsule

Thus, the percentage deviation of individual net weight must not exceed in the range of less than 300 mg.

NO.	MASS OF CAPSULE (mg)	MASS OF EMPTIED CAPSULE (mg)	MASS OF POWDER CAPSULE = (MASS OF CAPSULE - MASS OF EMPTIED CAPSULE) (mg)	CALCULATIONS	PERCENTAGE DEVIATION (%)
1	352.00	61.70	290.30	297.66 mg – 290.30 mg = 7.36 mg 7.36 mg/297.66 mg X 100% = 2.47%	2.47%
2	353.20	59.50	293.70	297.66 mg – 293.70 = 3.96 mg 3.96 mg/297.66 mg X 100% = 1.33%	1.33%
3	345.70	60.30	285.40	297.66 mg – 285.40 mg = 12.26 mg 12.26 mg/297.66 mg X 100% = 4.12%	4.12%
4	368.90	61.60	307.30	297.66 mg – 307.30 mg = -9.64 mg -9.64 mg/297.66 mg X 100% = -3.24%	-3.24%
5	366.50	63.20	303.30	297.66 mg - 303.30 mg = -5.64 mg -5.64 mg/297.66 mg X 100% = -1.89%	-1.89%
6	373.70	65.20	308.50	297.66 mg – 308.50 mg = -10.84 mg  -10.84 mg/297.66 mg X 100% = -3.64%	-3.64%
7	346.50	57.70	288.80	297.66 mg – 288.80 mg = 8.86 mg 8.86 mg/297.66 mg X 100% = 2.98%	2.98%
8	361.80	63.20	298.60	297.66 mg – 298.60 mg = -0.94 mg -0.94 mg/297.66 mg X 100% = -0.32%	-0.32%
9	367.00	65.20	301.80	297.66 mg – 301.80 mg = -4.14 mg -4.14 mg/297.66 mg X 100% = -1.39%	-1.39%
10	367.20	63.10	304.10	297.66 mg – 304.10 mg = -6.44 mg -6.44 mg/297.66 mg X 100% = -2.16%	-2.16%
11	345.00	57.40	287.60	297.66 mg – 287.60 mg = 10.06 mg 10.06 mg/297.66 mg X 100% = 3.38%	3.38%
12	371.60	61.00	310.60	297.66 mg – 310.60 mg = -12.94 mg -12.94 mg/297.66 mg X 100% = -4.35%	-4.35%
13	363.00	62.00	301.00	297.66 mg – 301.00 mg = -3.34 mg -3.34 mg/297.66 mg X 100% = -1.12%	-1.12%
14	352.50	63.50	289.00	297.66 mg – 289.00 mg = 8.66 mg 8.66 mg/297.66 mg X 100% = 2.91%	2.91%
15	361.80	58.10	303.70	297.66 mg – 303.70 mg = -6.04 mg -6.04 mg/297.66 mg X 100% = -2.02%	-2.02%
16	353.60	63.90	289.70	297.66 mg – 289.70 mg = 7.96 mg 7.96 mg/297.66 mg X 100% = 2.67%	2.67%
17	349.50	60.40	289.10	297.66 mg – 289.10 mg = 8.56 mg 8.56 mg/297.66 mg X 100% = 2.88%	2.88%
18	376.00	61.80	314.20	297.66 mg – 314.20 mg = -16.54 mg -16.54 mg/297.66 mg X 100% = -5.56%	-5.56%
19	351.60	64.00	287.60	297.66 mg – 287.60 mg = 10.06 mg 10.06 mg/297.66 mg X 100% = 3.38%	3.38%
20	359.00	60.10	298.90	297.66 mg - 298.90 mg = -1.24 mg -1.24 mg/297.66 mg X 100% = -0.42%	-0.42%

DISCUSSION :

1)      Limitation for 20 tablets

Not more than 2 of the individual masses deviate from the average mass by more than the percentage deviation shown in table below and none deviates by more than twice that percentage.

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

From the results and calculations, it can be seen that the percentage deviation for test uniformity of 20 tablets does not exceed the limitation which has been restricted (more than 250 mg).

2)      Limitation for 20 capsules

Not more than two of the individual weights deviate from the average weight by more than the percentage deviation shown in the table below, and none deviates by more than twice that percentage.

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

From the results and calculations, it can be seen that the percentage deviation for test uniformity of 20 capsules does not exceed the limitation which has been restricted (less than 300 mg)

CONCLUSION :

Thus, the tablet contains the correct amount of active ingredients and also their excipient and they are uniformly distributed in the tablet mass. The compounded powder contains the correct amount of active ingredients and that the capsule components are uniformly distributed in the powder mass.


REFERENCES :

1)     http://pharmatreasures.blogspot.com/2012/05/tablet-weight-variation-and-uniformity.html

2)     http://www.thefreedictionary.com/tablet

3)     http://www.slideshare.net/mallikarjunvasm/quality-control-tests-for-tablets