#ethers

Omeprazole (C₁₇H₁₉N₃O₃S) is a drug used to treat acid reflux, stomach ulcers, and indigestion. Under standard conditions, it is a white powder that is sparingly soluble in water.

Omeprazole acts as an irreversible proton-pump inhibitor. It binds permanently to active H⁺/K⁺-ATPase systems found in the stomach lining, preventing H⁺ ions from being shuttled into the stomach. This causes a reduction in gastric acid production.

Being lipophilic, it is readily absorbed by the parietal cells of the stomach, where it undergoes an acid-catalysed rearrangement to form a sulfenic acid, which exists in equilibrium with the sulfenamide. The sulfenamide, which is the active form of the drug, can then react with a cysteine residue in the ATPase to form a covalent bond with it.

As active H⁺/K⁺-ATPase pumps are activated upon consumption of food, omeprazole should only be taken on an empty stomach, and food should only be taken 30-60 minutes after.

Proton-pump inhibitors should only be taken in appropriate doses when needed, as they have been shown to interfere with absorption of nutrients since gastric acid is essential for the digestion of food and release of nutrients.

Omeprazole can be synthesised via a multi-step process from 2,3,5-trimethylpyridine.