Question

A drug unstable to heat but stable to moisture should be dried by _______

• A. Tray
• B. Fluidized bed
• C. Freeze
• D. Drum

Hint:

Fluidized bed drying reduces drying time and is useful when rapid drying with less heat exposure is required.

Answer 1

The Correct Option is B

Concept:
Drying method is selected according to the nature of the drug, especially its sensitivity to heat and moisture.

Step 1: Understanding the condition.
The drug is unstable to heat, so excessive heating should be avoided. The drug is stable to moisture, so moisture exposure is not the main concern.

Step 2: Fluidized bed drying.
Fluidized bed drying gives efficient drying due to good contact between hot air and particles. The drying time is short, so heat exposure is reduced.

Step 3: Why other methods are less suitable.
Tray drying may expose the drug to heat for a longer time.
Drum drying uses high heat and is not suitable for heat-sensitive drugs.
Freeze drying is generally used when the material is highly heat sensitive and often moisture sensitive, but the given correct choice is fluidized bed drying.

Step 4: Final answer.
Hence, the suitable method is fluidized bed drying. \[ \boxed{\text{Fluidized bed}} \]