dissolution test

A dissolution test watches how fast a drug comes out of its dosage form and into solution, by dropping a tablet or capsule into a vessel of warm fluid and sampling the liquid over time. It answers a practical question: once swallowed, how quickly does the active ingredient become available to be absorbed?

The product is placed in a defined volume of medium (often a buffer at 37 degrees Celsius, body temperature) and stirred at a set speed in a standard apparatus. Samples are pulled at fixed time points and analysed to find the percentage of label claim dissolved. Results are usually expressed as a dissolution profile or against a single-point limit such as not less than 80 percent dissolved in 30 minutes (often labelled Q).

Dissolution is a key quality and performance test because, for many drugs, dissolution is the slow step that controls absorption. It is widely used for batch release, for detecting formulation or process changes, and as a tool in developing in-vitro-in-vivo correlations — though an in-vitro result only predicts in-vivo behaviour when the method has been shown to be discriminating and relevant.