Question

A powder has a Carr's compressibility index in the range of 12-16. The flowability of the powder will be

• A. Fair
• B. Excellent
• C. Good
• D. Very poor

Hint:

Lower Carr's index indicates better flowability, which reduces problems like segregation and inconsistent dosing during manufacturing.

Answer 1

The Correct Option is C

Carr's Compressibility Index (CCI) is an indirect measure of powder flowability and packing ability. It is calculated using bulk density and tapped density of the powder as: \[ \text{CCI} = \frac{\text{Tapped density} - \text{Bulk density}}{\text{Tapped density}} \times 100 \] The flowability categories based on CCI values are: - 5-10: Excellent flow
- 11-15: Good flow
- 16-20: Fair flow
- 21-25: Poor flow
- > 25: Very poor flow
Since the given Carr's index is in the range 12-16, it falls in the "Good" flowability range, indicating the powder will flow well enough for typical pharmaceutical processing but is not excellent. This parameter is critical in tablet formulation and capsule filling to ensure uniformity and ease of processing.

Answer 2

Carr's compressibility index estimates how easily a powder flows by comparing how much it settles when tapped. Working through each flowability label against the standard index bands shows which one covers a reading of 12-16.

1. Fair: A fair flow rating corresponds to a higher compressibility index, roughly 16-20, where the powder shows noticeably more particle to particle friction and needs help, such as vibration or glidants, to flow smoothly. A reading of 12-16 sits mostly below this band.
2. Excellent: Excellent flow belongs to the lowest index values, roughly 5-10, where particles pack down very little on tapping because they slide past each other with almost no resistance. An index of 12-16 is clearly higher than this, so the powder is not flowing that freely.
3. Good: A good rating covers the band just above excellent, roughly 11-15, where the powder still compacts only moderately on tapping and flows well enough for most tableting and capsule filling operations without extra flow aids. A reading of 12-16 falls squarely in this range.
4. Very poor: This label applies to much higher index values, generally above 25, where the powder is highly cohesive and packs down heavily on tapping, often needing forced feeding to move at all. A value of 12-16 is far below this.

Placed against the standard Carr's index scale, a reading of 12-16 lands in the band used for good flow, not excellent, fair, or very poor flow.

So the correct answer is Good.