<prompt> Despite their sho half lives2hrs proton pump inhibitors cause a prolonged suppresion of acid secretiinupto 48hr because:They are prodrugs and undergo activation graduallyThey exit from the palsma and enter acid secretory canaliculi and stay there blocking the secretion of acid for a long timeThey irreversibly inhibit the proton pump molecule and hence,acid secretion requires synthesis of new proton pumpsThey are available as enteric coated capsules,from which drug is gradually released  <response>: They irreversibly inhibit the proton pump molecule and hence,acid secretion requires synthesis of new proton pumpsref Rang and Dale 5e p370-371, goidman gilman 12e p1311-1312 The activated form of PPI binds covalently with sulfahydryl groups of cysteine in the H K atpase ,irreversbly inacativating the pump molecule.acid secretion resumes only after new pump molecules are synthesized and inseed into the luminal membranes ptoviding a prolonged suppresion of acid secretion despite the much shoer pladma half lives of the parent compounds. 