In vitro evaluation of the antacid activity of Saint-Yorre and Vichy Celestins mineral waters in the << artificial stomach-duodenum >> model.

The antacid activity of Saint-Yorre and Vichy Celestins mineral waters was assessed in vitro using the <<artificial stomach-duodenum>> model according to similar modalities used for antacid drug evaluation. The antacid effect due to antacid salts and the antacid effect due to dilution by addition of 150 ml of water to the gastric contents were distinguished by using a non mineral water as reference (Charrier water). The Theoretical Maximal Antaci d Capacity (TMAC) in response to the addition of 150 ml of test water to 10 0 ml of 0.1 N hydrochloric acid solution was 77.5 mmol with Saint-Yorre, 79 .5 mmol with Vichy Celestins and 53.7 mmol with Charrier water. The dilutio n-induced resistance to acidification corresponded to a TAMC of 53.7 mmol a nd the bicarbonate content corresponded to a TMAC of 23.7 mmol for Saint-Yo rre and 25.4 mmol for Vichy Celestins, corresponding to about one-third of the total antacid activity. The greater bicarbonate content of Saint-Yorre water resulted in a brief pH-rise of gastric contents of 4.9 vs 1.91 with V ichy Celestins water. The lag-times to recover the initial pH were similar for Saint-Yorre and Vichy Celestins waters, explaining the identical values of TMAC; these lag-times were longer than with Charrier water. The total a ntacid capacity of bicarbonated waters was similar to that of some antacid drugs, although the antacid mechanisms are different. Bicarbonated mineral waters reduced the acid concentration in the gastric contents and the acid load entering the duodenum. The greater pH-rise induced by Saint-Yorre wate r could be an argument to explain its antidyspeptic effect by increasing ga stric emptying rate.