Table 1 . Summary of recent progresses in granulation techniques and technologies .

Techniques/ technologies	Description	Granule Characteristics	Merits	Limitations	Equipment
Pneumatic dry granulation	• Dry granulation • Mild Compaction and pneumatic classification	√ Porous, highly compressible √ Taste masking √ Fast disintegration √ Release time modification	↑ Drug loading √ Thermolabile and moisture sensitive drugs ↑ Product stability ↓ Cost and waste	X Recycled granule quality X Segregation potential X Friability	√ Roller compaction with air stream or vacuum
Reverse wet granulation	• Wet granulation • Water or solvent is granulating liquid	√ Uniform wetting √ Uniform erosion	↓ Particle size √ Spherical shape √ Poorly water soluble drugs	X Larger particle size1 X Lower porosity X Many problems similar to conventional wet granulation	√ High speed mixer
Steam granulation	• Wet granulation • Steam is granulating liquid	↑ Diffusionrate ↑ Uniform distribution ↑ Surface area √ Spherical shape	√ Eco-friendly √ Sterility Process time √ No solvent use √ No health hazards	X Local over heating/wetting X High energy inputs X Thermolabile drugs X Limited binders	√ High speed mixer with steam generator/regulator
Moisture-Activated Dry Granulation	• Wet granulation 1-4% water is granulating liquid and moisture-absorbing material	√ Uniform size ↑ Flowability ↑ Compressibility	√ Less energy input √ No drying process √ Wide applicability √ Continuous processing ↓ Shorter process time Process variables	X Moisture sensitive drugs X Impossible high drug loading X Limited absorbents	√ High-shear mixer coupled with a sprayer
Thermal adhesion granulation	• Wet granulation • Low water/solvent is granulating liquid and heating at 30-130 °C	√ Flowability √ Friability Tensile strength	↑ Drug loading √ No drying process Dust	X High energy inputs X Thermolabile and moisture sensitive drugs X Limited binders	√ Tumble blender or similar equipment coupled with heating system
Melt granulation	• Wet granulation • Meltable binder as granulating liquid, heating at 50–90 ◦C	√ Possible modified release ↑ Dissolution	√ No water or solvent √ No drying process ↓ Energy input ↓ Cost and process time √ Water sensitive drugs	X Thermolabile drugs X Limited binders	√ High shear mixer √ Fluidized bed
Freeze granulation	• Wet granulation • Spray freezing and subsequent freeze drying for slurry or suspensions	√ Uniform size √ Flowability √ Spherical shape	↑ Granule homogeneity √ Thermolabile drugs √ Granule density control ↓ Material waste	X Limited solvent medium X Only suitable for conversion of liquid slurry or suspension to granules	√ Spray freezer coupled with freeze dryer
Foam granulation	• Wet granulation • Foam as granulating liquid	√ Uniform binder distribution √ No over wetting ↑ Surface area	↓ Water requirement No spray nozzle use √ Low water required ↓ Cost and process time √ Water sensitive drugs	X Moisture sensitive drugs X Limited binders	√ High shear mixer or fluidized bed granulator coupled with foam generator/regulator

‏ ↓ reduced or decreased; ↑ increased or high; √ possibility or suitability or availability; X Unsuitable or not applicable. ¹ at lower binder concentration.