The role of the stomach in drug absorption as observed via absorption rate analysis.

Absorption rate analysis (ARA) was introduced in 2011 as a no-cost investigative tool for elucidating the details of drug absorption recorded in individual plasma time-concentration profiles. The method continues to be refined since its introduction, so that a new article offering more advanced applications of the method is appropriate. The stomach has been observed to exert considerable influence on the drug absorption process beyond the usual issues of drug solubility and stability in the gastric environment. This article is intended to demonstrate how readers can use ARA to reveal common factors affecting drug absorption. A newly introduced technique is to make observations concerning individual subjects, then assemble those individual observations to reveal factors not observable on an individual basis. This technique considerably increases the utility of ARA for revealing potential barriers to drug absorption.