Question

Enteric coating is done with the following material

• A. Sodium starch glycolate
• B. Cellulose acetate phthalate
• C. Starch
• D. PEG-400

Hint:

Enteric coatings are usually made from materials like cellulose acetate phthalate that are stable in acidic conditions but dissolve in the intestines.

Answer 1

The Correct Option is B

Step 1: Understanding enteric coating.
Enteric coating is a polymer barrier applied to oral medication to prevent it from dissolving in the stomach. It protects the drug from acidic stomach conditions and releases it in the intestines.
Step 2: Analyzing the options.
(A) Sodium starch glycolate: This is used as a disintegrant, not for enteric coating.
(B) Cellulose acetate phthalate: Correct — This is a common material used for enteric coating as it resists stomach acid and dissolves in the alkaline environment of the intestines.
(C) Starch: Starch is a binding agent, not suitable for enteric coating.
(D) PEG-400: This is a plasticizer, not used for enteric coating.
Step 3: Conclusion.
The correct answer is (B) Cellulose acetate phthalate as it is the material used for enteric coatings.

Answer 2

An enteric coating material must have one defining property: it must stay intact in the acidic stomach and only dissolve in the more alkaline intestinal environment. Testing each option against this pH-dependent solubility requirement identifies the right material.

1. Sodium starch glycolate: This is a superdisintegrant, designed to rapidly absorb water and swell to help a tablet break apart quickly, the opposite function of a coating meant to delay release.
2. Cellulose acetate phthalate: This polymer is specifically insoluble in the acidic pH of the stomach but becomes soluble once it reaches the higher pH of the small intestine, which is precisely the pH-triggered solubility behavior that defines an enteric coating material.
3. Starch: Starch is primarily used as a binder or disintegrant in tablet formulation and has no pH-dependent solubility behavior suitable for enteric coating.
4. PEG-400: Polyethylene glycol 400 is commonly used as a plasticizer or solvent/vehicle in formulations, and it does not have the acid-resistant, intestine-soluble property required of an enteric coat.

Only one of these materials has the necessary pH-dependent solubility behavior.

Therefore, the correct answer is Cellulose acetate phthalate.