Gastrointestinal transit and drug absorption

Toshikiro Kimura, Kazutaka Higaki

Research output: Contribution to journalReview articlepeer-review

162 Citations (Scopus)


The gastrointestinal (GI) absorption of orally administered drugs is determined by not only the permeability of GI mucosa but also the transit rate in the GI tract. It is well known that the gastric emptying rate is an important factor affecting the plasma concentration profile of orally administered drugs, and the intestinal transit rate also has a significant influence on the drug absorption, since it determines the residence time of the drug in the absorption site. The reason why the residence time is also a critical factor for drug absorption is that there is the site difference in absorbability for some drugs. We have developed the GI-Transit-Absorption Model (GITA Model) to analyze and predict the drug absorption kinetics by taking into account both the two factors, i.e. GI transit and drug absorbability including its site difference. GITA Model has been already evidenced to be very useful for estimating the absorption kinetics of drugs with various characteristics and applied to assess the human data in combination with the gamma scintigraphy. In this review, the importance of GI transit rate in determining the absorption kinetics and the bioavailability of orally administered drugs is discussed mainly employing GITA Model and the results obtained by the model.

Original languageEnglish
Pages (from-to)149-164
Number of pages16
JournalBiological and Pharmaceutical Bulletin
Issue number2
Publication statusPublished - Feb 2002


  • Bioavailability
  • Drug absorption
  • Gamma scintigraphy
  • Gastrointestinal tract
  • Residence time
  • Transit rate

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science


Dive into the research topics of 'Gastrointestinal transit and drug absorption'. Together they form a unique fingerprint.

Cite this