Researchers in Mexico tested expired omeprazole, a common heartburn drug, as a corrosion inhibitor for AISI 1018 carbon steel in a chloride-sulfate solution that mimics marine-industrial environments. At 75 ppm, the drug formed a protective film that reached roughly 70% inhibition efficiency after 72 hours of immersion. The film broke down by 96 hours, and some lower or higher doses actually accelerated corrosion, so the effect is highly dependent on concentration and time. Traditional corrosion inhibitors often rely on chromium or lead compounds, which face tightening regulation under rules like TSCA and RoHS. Repurposing expired pharmaceuticals could divert drug waste from disposal while offering a greener alternative. The researchers caution that toxicity, leaching, biodegradation, and life-cycle impacts still need to be studied before any environmental benefit can be claimed.
