Characterization of a new crystalline synthetic gastric antacid, almagate.

A new crystalline hydrated aluminium-magnesium hydroxycarbonate, almagate (Almax) is described. It has been shown to have an empirical formula Al2 Mg6(OH)14(CO3)2 X 4 H2O X. X-ray diffraction spectra indicate that it is different from other related antacids and that its crystal structure is made up of brucite layers, in which magnesium is replaced by aluminium in the ratio of 3 to 1, interposed with negatively charged layers containing carbonate ions and water. Analysis of the IR spectra suggests that the interstitial carbonate is coordinated to both metals. Differential thermal analysis demonstrates that almagate has good thermal stability and measurement of its antacid activity shows that it has a rapid neutralization velocity and a high acid consuming capacity.