AN IN VITRO MODEL TO REPRODUCE THE MECHANICS AND THE ABSORPTION IN THE GASTROINTESTINAL TRACT

After its oral administration, a pharmaceutical form is subjected to several factors potentially influencing the drug release. Once it is assumed, the dosage form reaches the stomach, through the esophagus, and from there, at the end of the digestive function, it passes in the intestine where it is absorbed through the intestinal walls and distributed in the circulatory system. The main goal of pharmacokinetic analysis is the prediction of the drug behavior after an administration: the in-vitro tests serve as a guide in estimating the drug release profiles. Thus, to develop a device simulating the drug release due to the oral administration, the physiology has to be considered. Conventionally, the release of a drug from a pharmaceutical is analyzed by USP-approved apparatuses [1] which are limited to analyze what happens during the dissolution step: the most widely used is the USP Apparatus II. During the last decades, different devices not approved officially by the Pharmacopoeia have been proposed to reproduce the gastrointestinal environment, but they still lack of an appropriate reproduction of the mechanical conditions [2]. The aim of this work is to design and test an in-vitro device which is able to simulate the real mechanical history that a pharmaceutical form undergoes in the stomach and to evaluate the influence of the fluid-dynamic conditions on the release profiles. Moreover, the absorption across the intestinal wall is simulated, obtaining the release profiles both in the gastrointestinal tract and in the circulatory system across the intestinal tract, reproducing more accurately the real physiology than the conventional tests.