Physical and Chemical Tests of Pharmaceutical Tablets
Pharmaceutical tablets must meet their physical specifications and quality standards for ensuring safety and efficacy. These include weight variation, content uniformity, hardness, thickness, friability, disintegration, and dissolution. These factors must be controlled during production (in-process controls) and verified after the production of each batch to ensure that established product quality standards are met.
Weight Variation
The USP general chapter〈905〉contains a test guideline for determination of dosage form uniformity by weight variation for tablets. In the test, 10 tablets are weighed individually, and the average weight is calculated. The tablets are assayed, and the content of active ingredient in each of the 10 tablets is calculated assuming homogeneous drug distribution.
Content Uniformity
The USP general chapter〈905〉also contains a test guideline for determination of content uniformity. In this test, 10 dosage units are individually assayed for their content according to the method described in the individual monograph or validated method.
Tablet Hardness
In general, tablets should be sufficiently hard to resist breaking during normal handling and yet soft enough to disintegrate properly after swallowing.
Tablet Thickness
The thickness of a tablet depends on the compaction characteristics of the fill material, and the force or pressure applied during compression. It is important for smooth blistering.
Tablet Friability
A tablet’s durability may be determined through the use of a friabilator, which determines the tablet’s friability, or tendency to crumble, by allowing it to roll and fall within the drum. The tablets are weighed before and after a specified number of rotations, and any weight loss is determined.
Tablet Disintegration
For the medicinal agent in a tablet to become fully available for absorption, the tablet must first disintegrate and discharge the drug to the body fluids for dissolution. That’s why all tablets must pass a test for disintegration, which is conducted in vitro using a disintegration tester.
Tablet Dissolution
Dissolution is a critical quality attributes of pharmaceutical tablets. Dissolution studies in the early stages of a product’s development allow differentiation between formulations and correlations identified with in vivo bioavailability data. Consistent in vitro dissolution testing ensures bioequivalence from batch to batch.
Tablet Assay
Assay is the primary test of pharmaceutical tablets. It ensures the tablets contain required amount of API.
