When a substance forms a solution, this process is called Dissolution. When performing the test with a dissolution tester, the release rate and total drug amount over time is measured. The dissolution rate/amount of an Active Pharmaceutical Ingredient (API) is important for corelating product safety and efficacy. Through a consolidated effort, the instruments used to generate a dissolution rate have been standardized through various compendial initiatives.
Dissolution testing uses a defined setup with specific conditions to evaluate the performance of the product. Compendia describes seven standardized dissolution apparatus, the most commonly dissolution equipment used being basket (USP 1), paddle (USP 2) and flow-through cell (USP 4).