An artificial stomach-duodenum model for the in-vitro evaluation of antacids.

To improve the dynamic in-vitro evaluation of the effects of antacids, we have developed the 'artificial stomach' model by adding a 'duodenal reservoir' to receive the gastric emptying flux and simulated bicarbonate secretion, thus constituting an 'artificial stomach-duodenum' model. With this model we measured antacid-induced resistance to gastric acidification, and simultaneously evaluated the effect of antacid activity on the duodenal milieu. The model also permitted evaluation of the antacid effects of proteins (as natural antacids), and of drugs containing aluminium phosphate, alone or combined with magnesium oxide, or aluminium and magnesium hydroxides.

[In vitro evaluation of antacid activity in gastric acid secretion in static and dynamic systems].

A valid in vitro evaluation of antacid capacity should consider: 1) the intragastric pH-range; 2) the antacid mechanism; 3) the dependence of antacid activity from intraluminal flux variations; 4) the interaction between proteins and antacids. Pharmacologically, a static method allows 1) to quantify H+ binding sites at different pH-end points of the titration: pH 3.0, 2.