The quality of a solid oral dosage form, such as a tablet or capsule product, may be defined as its ability to provide expected and consistent (reproducible) drug levels in plasma/blood. The product is introduced into the GI tract through the oral cavity (mouth) to release its drug, which gets dissolved in the aqueous milieu and gets transferred into the bloodstream to produce its therapeutic effects.
This drug transfer from the GI tract to the bloodstream is described by different terminologies, often interchangeably, such as permeability, absorption and bioavailability of the drug. However, these terminologies have distinct meanings, and for clarity purposes, should not be interchangeably used. The purpose of this article is to describe and explain these terminologies to facilitate appropriate development and evaluation of the products in particular for the use of in vitro drug dissolution testing. Please click here for the complete article