How does an enteric-coated aspirin behave compared with regular aspirin?
Regular aspirin can dissolve and start releasing in the stomach, where the acidic environment speeds dissolution. Enteric coating is designed to prevent that by keeping the tablet intact in the stomach, then dissolving later in the small intestine where the pH is higher. [1]
What happens in the stomach, and why does that matter for release?
In the stomach (low pH), the enteric coating is intended to stay insoluble, so aspirin release is delayed rather than occurring immediately after swallowing. This delays exposure of the stomach lining to aspirin and helps shift where the drug begins dissolving. [1]
When does the coating dissolve in the intestines?
Enteric coatings typically dissolve after the tablet passes into the small intestine, where the pH rises. Once the coating dissolves, aspirin can disintegrate and release in the intestinal environment. This is the mechanism behind the “delayed-release” behavior. [1]
Does pH alone control release, or do other factors play a role?
pH is the main trigger, but real-world release can vary with factors that change stomach-to-intestine transit and local pH, such as food intake and individual gastrointestinal conditions. Those variations can affect how quickly the coating reaches conditions that cause it to dissolve and how consistently release occurs. [1]
Why do manufacturers use enteric coating for aspirin?
The main goal is to delay aspirin release away from the stomach and into the intestines. That can change the drug’s local effects in the upper GI tract compared with immediate-release aspirin, which is relevant because aspirin can irritate the stomach lining when it is released there. [1]
What does “enteric coating” mean in practice for patients?
For patients, the practical effect is that enteric-coated aspirin is not supposed to start releasing right after it reaches the stomach. Instead, the coating is meant to protect the tablet through the stomach and then allow drug release after it enters the intestines. [1]
Key limitation: enteric coating doesn’t eliminate GI risk
Enteric-coated aspirin still releases aspirin somewhere in the GI tract, and it can still cause GI side effects. Delaying release may reduce stomach irritation relative to immediate-release forms, but it does not make aspirin GI effects disappear. [1]
Sources
[1] https://en.wikipedia.org/wiki/Enteric-coated_tablet