PPI means proton pump inhibitor.
There are five important 'proton pump inhibitors' available in market. Such as - Omeprazole, Lansoprazole, Pantoprazole, Rabeprazole & Esomeprazole.
Mode of action: 'Proton pump inhibitors' interfere in the final stage of gastric acid production by blocking i.e forming a covalent bond to two sites of the H+, K+ -ATPase enzyme system ('proton pump') at the secretory surfaces of the gastric parietal cells. This leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. The binding to the H+, K+ -ATPase enzyme system results in an anti secretory effect of long duration persisting more than 24 hours.