An enteric coating on a tablet is a specialized outer layer designed to control precisely where and when the medication or supplement inside is released within the body. This coating acts as a protective barrier, ensuring the tablet’s contents reach their intended destination in the digestive system. Its primary role is to optimize the therapeutic outcome of the medication.
What Enteric Coating Is
An enteric coating is a polymer layer that encapsulates a tablet or capsule. These polymers are engineered to remain intact when exposed to highly acidic conditions, such as those found in the stomach. However, they are designed to dissolve once they encounter a higher pH environment, typically present in the small intestine. Common materials used for these coatings include cellulose acetate phthalate, hydroxypropyl methylcellulose phthalate, and methacrylic acid copolymers.
Protecting Contents from Stomach Acid
One main purpose of an enteric coating is to shield the tablet’s contents from degradation by stomach acid. The human stomach maintains a highly acidic environment, with a pH typically ranging between 1.5 and 2.0. This strong acidity can break down certain active pharmaceutical ingredients (APIs) or sensitive compounds, such as enzymes or probiotics, rendering them ineffective before they can be absorbed. The enteric coating provides a crucial barrier, preventing direct contact between the medication and the gastric acid. This protection ensures the integrity and effectiveness of the drug as it passes through the stomach.
Ensuring Release in the Intestine
The second primary purpose of an enteric coating is to ensure the medication is released specifically in the small intestine. As the coated tablet exits the stomach and enters the small intestine, it encounters a significantly higher pH environment, typically ranging from 6 to 9. This change in acidity triggers the dissolution of the enteric coating, allowing the drug to be released. Many drugs are best absorbed in the small intestine due to its large surface area and more permeable membranes, which are well-suited for nutrient and drug absorption.
Releasing certain medications directly in the stomach could also lead to irritation or unwanted side effects. For instance, some drugs, like nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin, can irritate the stomach lining, potentially causing discomfort or even ulcers. By delaying release until the small intestine, enteric coatings help minimize direct contact with the stomach mucosa, thereby reducing the risk of gastrointestinal irritation.
Common Applications and Usage Advice
Enteric coatings are utilized for a variety of medications and supplements. Examples include aspirin, often coated to reduce stomach irritation, and certain enzymes or probiotics that would otherwise be destroyed by stomach acid. Proton pump inhibitors, used to treat acid-related disorders, also commonly feature an enteric coating to protect their active ingredients. Fish oil supplements sometimes use this coating to prevent degradation in the stomach and avoid an unpleasant aftertaste.
It is important to follow specific administration instructions for enteric-coated tablets. To maintain the integrity of the coating and ensure the medication works as intended, these tablets should not be crushed, chewed, or split. Doing so would destroy the protective layer, potentially leading to reduced effectiveness of the drug or stomach irritation. Patients should always consult the medication label or a healthcare professional for advice on whether to take these tablets with or without food, as instructions can vary.