Criteria of an ideal antacid preparation:

• The antacid should not be absorbable or cause systemic alkalosis
• The antacid should not be a laxative or causes constipation
• The antacid should exert its effect rapidly and over a long period of time
• The antacid should buffer in the pH 4-6 range
• The reaction of the antacid with gastric HCl acid should not cause a large evolution of gas
• The antacid should probably inhibit pepsin