Question

Identify the diffusible substance for mixtures preparation

• A. Caffeine citrate
• B. Atropine sulphate
• C. Borax
• D. Bismuth carbonate

Hint:

In pharmaceutical formulations, ensure the selected substance is easily diffusible for even distribution in the mixture.

Answer 1

The Correct Option is A

Step 1: Understanding diffusible substances.
For mixtures preparation, a diffusible substance is one that can easily disperse or spread out in a mixture. The diffusibility of a substance plays an important role in homogeneity.
Step 2: Analyzing the options.
(A) Caffeine citrate: Correct — Caffeine citrate is a diffusible substance used in pharmaceutical preparations, especially in mixtures where even distribution is required.
(B) Atropine sulphate: This is not as diffusible as caffeine citrate.
(C) Borax: Borax is typically used in other preparations but is not known for its diffusibility in mixtures.
(D) Bismuth carbonate: Bismuth carbonate is not a typical diffusible substance for mixtures preparation.
Step 3: Conclusion.
The correct answer is (A) Caffeine citrate, which is used for its ability to diffuse in mixtures.

Answer 2

In pharmaceutical mixture (suspension) formulation, insoluble solids are classified as either "diffusible" (they stay dispersed through the vehicle fairly easily without needing a special suspending agent) or "indiffusible" (they settle quickly and need a suspending agent to stay dispersed). Sorting each option into one of these two categories answers the question.

1. Caffeine citrate: This is treated as a diffusible substance in mixture preparation - being a soluble, readily dispersible citrate salt, it distributes evenly through the vehicle without requiring a separate suspending agent.
2. Atropine sulphate: Atropine sulphate is used in very small, potent doses and is not typically categorized under the diffusible-solids grouping used for bulkier suspended powders in mixtures.
3. Borax: Borax is generally used for other formulation purposes (such as a preservative or pH-adjusting agent) rather than being classed among diffusible solids for suspension mixtures.
4. Bismuth carbonate: Heavier, denser insoluble powders like bismuth carbonate are generally classed as indiffusible substances, meaning they settle rapidly and need a suspending agent (such as tragacanth or acacia) to stay dispersed, the opposite of what's being asked.

Sorting each substance by diffusible/indiffusible behavior in a mixture identifies only one match.

Therefore, the correct answer is Caffeine citrate.