Pumaprazole is imidazopyridine derivative patented by Byk Gulden Lomberg Chemische Fabrik GmbH for the treatment of gastrointestinal diseases. Pumaprazole acts as a reversibly binding acid pump antagonist. Pumaprazole differs from covalently binding proton pump inhibitors (PPIs), such as omeprazole, both with respect to chemical structure and mode of interaction with the gastric H(+)/K(+)-ATPase. In preclinical models, the single dose of Pumaprazole is able to elevate intragastric pH in the dog with gastric fistula under pentagastrin or carbachol stimulation from pH 1 to about pH 7 while still displaying a dose-dependent, well-controllable duration of action of a few hours.