"In vitro" dissolution tests for solid oral dosage forms.

©2010 Particle Sciences, Inc. All rights reserved. the drug substance and involves two steps: dissolution and absorption (or permeability). Understanding the multi-step dissolution process is essential to proper in vitro method development. Dissolution is the process of extracting the API out of the dosage form solid-state matrix into solution within the gastrointestinal tract. Absorption is the process of transporting the drug substance from the gastrointestinal lumen into the systemic circulation. Dissolution testing is an in vitro method that characterizes how an API is extracted out of a solid dosage form. It can indicate the efficiency of in vivo dissolution but does not provide any information on drug substance absorption. Pharmacokinetic data supplements and provides additional information regarding API absorption rate. Selection of the appropriate in vitro conditions (media and hydrodynamics) that simulate the in vivo conditions can lead to the generation of successful IVIVC or at the very least, in vitro-in vivo relations (IVIVR).3 Conditions that are optimal for QC purposes may not be applicable for establishing IVIVC so it may be necessary to use two dissolution tests to meet different objectives such as development needs or regulatory demands.