Question

Titanium dioxide in gelatin mass components of capsule is a

• A. Tonicity contributor
• B. Viscosity inducer
• C. Opacifier
• D. Preservative

Hint:

Titanium dioxide is used in capsules primarily as an opacifier, giving them a white, opaque appearance to protect the contents from light.

Answer 1

The Correct Option is C

Titanium dioxide's defining property is that it's a bright white, light-scattering pigment, so we can match that to the right function.

1. Tonicity contributor: Relates to osmotic pressure, unrelated to a solid capsule shell's pigment.
2. Viscosity inducer: Relates to flow/thickness, not to optical opacity.
3. Opacifier: Correct - it blocks light transmission through the capsule shell, making it opaque.
4. Preservative: Titanium dioxide has no antimicrobial function.

So the correct answer is Opacifier.

Answer 2

A different way to reach the same conclusion is to think about why a capsule manufacturer would want an opaque shell in the first place, and check which option serves that practical purpose.

1. Tonicity contributor: There is no practical reason a solid capsule shell would need a tonicity-adjusting ingredient, since tonicity only matters for liquid formulations meant to match body fluid osmotic pressure.
2. Viscosity inducer: While the gelatin mass does need to be workable during manufacturing, titanium dioxide is not added for that reason - other excipients handle viscosity.
3. Opacifier: Manufacturers often want the capsule shell to mask the appearance of the fill material inside, protect light-sensitive actives from photodegradation, and give a consistent look across batches - titanium dioxide's opacifying property directly serves all of these goals.
4. Preservative: The practical need to prevent microbial spoilage in a capsule shell is addressed by actual antimicrobial preservatives, not by a pigment like titanium dioxide.

Only one of these functions matches the real manufacturing motivation for adding titanium dioxide.

Hence, the correct answer is Opacifier.