Quality Control (QC) tests for tablets
Quality of tablets should fulfill certain specifications:
1. The tablet should include the correct dose of the drug
(Weight uniformity and content uniformity test).
2. The drug should be released from the tablet in a
controlled and reproducible way (Dissolution test).
3. The tablet should show sufficient mechanical strength
to withstand fracture and erosion during manufacturing
and handling (Hardness and friability test).
4. The appearance of the tablet should be elegant and its
weight, size and shape should be consistent (Visual
observation, weight variation, thickness and diameter
tests of the tablet).
5. The tablet should be packed in a safe manner.
Good Manufacturing Practice (GMP)
A part of Good Manufacturing Practice
(GMP), the production run is monitored
under control chart. At regular intervals
During the course of manufacturing, the
operator must sample specified number of
tablets for testing (in-process control) e.g.
weight of tablet, tablet thickness, friability,
The major pharmacopoeias used widely are:
The British Pharmacopoeia (BP)
The United States
The European Pharmacopoeia
Official standards (Q. C. tests) for tablets
British Pharmacopoeia (B.P.) & US
1- Uniformity of content of active ingredient
(Uniformity of weight & Content uniformity)
2- Disintegration test.
3- Dissolution test.
4- Friability test.
USP mentions some Q.C. tests before the powder
is compressed e.g. powder fineness, density, …
Official Quality Control Tests for Tablets
Uniformity of content of active
Uniformity of weight
Quality control tests and specifications
• Some of properties (NOT TESTS) are
given in pharmacopoeias. The most
important for these are:
• Weight uniformity,
• Dose uniformity,
• The drug release in terms of tablet
disintegration and drug dissolution,
• Resistance of tablets to fracture in terms
of friability and harness testing, and
• The microbial quality of the product.
Pharmacopeias and non-compendial
Some test methods are described in
the pharmacopeias; others are not and
thus are referred to as "non-
Other tests must be controlled during
production (in-process control) and
verified after production.
There are many tests are frequently
applied to tablets for which there are
non-pharmacopoeial requirements but
will form a part of manufacture's
owner product specifications.
1- Tablet thickness.
2- Tablet hardness.
Micrometer (tablet thickness) Diameter Tester
"Monsanto" Tablet hardness tester
The Electronics Tablet Hardness, Thickness and
Measured Diagonally and orthogonal
4kg is a typical requirement
Uniformity Test for Active Ingredient:
To ensure a constant dose of drug
between individual tablets.
Traditionally, dose variation between
tablets is tested in two separate tests;
1- Weight uniformity
2- Content uniformity
Weight Uniformity Test
A. Weight uniformity Weigh 20 tablets
individually (i.e. determine the weight of each
Calculate the average weight of tablets =
Total weight of tablets/ Number of tablets
% Error for a tablet =
Difference between Actual tablet weight and
Average tablet weight x 100/ Average tablet
Not more than TWO of the individual tablet weights
deviate from the average weight (X) by more than 7.5%
Pharmaceutical form Average tablet Percentage
weight (X) deviation
80 mg or less 10
Tablets size 80- 250 mg 7.5
250 mg or more 5
Weight of each tablet % of error
1 99.8 -1.38827
Example for calculating
2 98 -3.16684 % of error = (99.8-101.205) X 100 = -1.388%
3 97.5 -3.66089 101.205
4 99 -2.17875
5 102 0.785534
6 100.6 -0.5978
7 101 -0.20256
Test result: Only one
8 104.6 3.354577
9 102 0.785534
10 103.2 1.971246 tablet (tablet number 13)
11 102.3 1.081962 deviated >7.5%,
12 100.4 -0.79542
13 109.8 8.492663
and this deviation (%error
14 101.2 -0.00494 8.49 %)
Tablets passed this test
15 103.2 1.971246
16 102 0.785534
17 99.5 -1.6847 successfully
18 98.4 -2.7716
19 97.5 -3.66089
20 102.1 0.884344
• 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 capsules intended
for oral administration where the range of size of the dosage
form available include 50 mg or smaller sizes.
• Tablet monographs with a content uniformity requirement
do not have weight variation requirements .
• For content uniformity test, representative samples of
30tablets are selected and 10 are assayed individually. At
least 9must assay within ±15% of the declared potency and
none may exceed ±25% .
USP design: content uniformity tests
According to United States Pharmacopoeia (USP), the
procedure for content uniformity test is:
Stage1: Take 10 units randomly and perform the assay.
* It passes the test if the relative standard deviation (RSD)
is less than 6% and no value is outside 85–115%.
* Fails the test if one or more values are outside 75–
Stage2: Take 20 more units and perform the assay
* Passes the test if RSD of all the 30 tablets is less than
7.8%, not more than one value is outside 85–115%, and
no value is outside75–125%. Or else the batch fails the
End of section thirty