Prescribing patterns of proton pump inhibitors: (why PPIs before meals are prescribed):

Not only do Proton Pump Inhibitors not work in the stomach directly, they are inactivated and destroyed by acid. Drug manufacturers have made two delivery methods to bypass the intensely acidic stomach juices. Almost all the PPIs are enteric coated and delayed release to be absorbed in the intestine and not released (and destroyed) in the stomach. This protects the drug but delays the effect. Also PPIs must be activated by food stimulating the parietal cell to make acid. Therefore to get the best effect of your medication, you should take it on an empty stomach half an hour to an hour before eating.

“PPIs to inhibit acid secretion when they are taken before meals. It has been hypothesized that pre breakfast dosing maximizes PPI efficacy because ATPase molecules (proteins) are able to accumulate in parietal cells during a prolonged overnight fast, making more ATPase molecules available for acid-catalyzed conversion to their actively secreting form by food ingestion.