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.

Evaluation of gastrointestinal motility directly from human pharmacokinetic data.

Since the 1980s, a considerable body of research has been dedicated to the development of in silico models for the prediction of human pharmacokinetic data based on absorption in a series of discreet intestinal compartments. While some of these models have been successfully used to predict future pharmacokinetic results or to explain previous results, evidence for compartmental absorption in individual pharmacokinetic data has not been published. This article presents in vivo evidence for compartmental drug absorption along with an empirical method for determining gastrointestinal (GI) tract location during absorption, using individual time-absorption rate profiles.