Enteric coating polymers are picked for how their solubility changes with pH, and cellulose acetate phthalate is a classic example, so following its pH behaviour through the gastrointestinal tract gives the release site.
- Liver: Nothing about an oral coated tablet routes it to the liver directly. Any drug reaching the liver does so afterward, through the bloodstream, not through direct tablet disintegration there.
- Intestine: CAP contains carboxylic acid groups that remain protonated and water-insoluble at the stomach's low pH (around 1 to 3), keeping the coat intact while it passes through. Once the tablet reaches the small intestine, where the pH rises above about 5 to 6, these groups ionise, the polymer becomes soluble, and the coat breaks down, releasing the core drug at this point.
- Oral cavity: The coat is stable at neutral to near-neutral pH for the short time the tablet spends being swallowed, so no release happens here.
- Stomach: This is the one location an enteric coat is built to avoid. Its acid-resistant design keeps the tablet from breaking apart while inside the acidic stomach.
Since the coating only dissolves once the pH rises past the stomach's acidic range, the correct answer is Intestine.