- Particle Shape influences surface area, flow, and packing of powders in pharmaceutical formulations.
- Particle Shape affects dissolution, stability, bioavailability, and product performance.
- While most techniques assume spherical particles, real particles often have irregular shapes (needle, plate, cube, etc.).
Shape Descriptors:
- Aspect Ratio = Length / Width
- Sphericity = Surface area of a sphere with same volume / Actual particle surface area
- Circularity = 4π × Area / Perimeter²
Methods to analyze shape:
- Optical and electron microscopy
- Image analysis software (automated detection and classification)
Importance:
- Particle shapes affect flow, packing, dissolution, and surface area.
- Needle-shaped particles may flow poorly; spherical particles flow better.
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