How does enteric coating change aspirin’s release in the stomach?
Enteric coating is a protective polymer layer on a tablet that is designed to survive the acidic environment of the stomach (low pH). Because the coating does not dissolve in acid, the tablet stays intact long enough to pass from the stomach into the small intestine.
Why does aspirin start dissolving after the tablet reaches the small intestine?
Once the coated tablet leaves the stomach and enters the small intestine, the environment becomes less acidic (higher pH). The enteric coating is formulated to dissolve or break down at that higher pH. When it breaks down, the aspirin tablet contents can dissolve and be absorbed, creating a delayed start to release.
What does “slow release” mean in practice?
With enteric-coated aspirin, the key “slow” effect is mainly delayed release (the dose doesn’t meaningfully release in the stomach). After the coating dissolves in the intestine, aspirin can be released and absorbed over the region of the gastrointestinal tract where the coating has cleared.
Does enteric coating affect aspirin’s absorption, or just where it dissolves?
It primarily changes where the drug is permitted to dissolve and be released. By preventing early gastric dissolution, it can also reduce direct exposure of aspirin to the stomach lining, which is one reason enteric-coated formulations are used when minimizing stomach irritation is a concern.
How is this different from extended-release (ER) aspirin?
Enteric-coated aspirin delays release by using pH-dependent coating that resists stomach acid and dissolves in the intestine. Extended-release products, by contrast, use different mechanisms (such as matrix or polymer-controlled diffusion) to slow the drug’s release rate over time, regardless of stomach acidity. Enteric coating and ER can be combined in some products, but they are not the same mechanism.