Dry granulation is a granulation technique where no liquid is used and is particularly required for drugs that are sensitive to moisture or heat. In this technique, powder particles are granulated under high pressure either by using slugging process or roller compaction process. The slugs or compacts then are milled to the desired particle size.


Dry Granulation Steps

  • Dispensing
  • Mixing
  • Slugging/compaction
  • Milling/sieving
  • Blending & Lubrication
  • Compression


Critical Parameters of Dry Granulation (roller compaction)

  • Pre-granulation blend uniformity
  • Pre-granulator screen
  • Fine-granulator screen
  • Flake thickness
  • Particle size distribution (PSD) and 
  • Flow properties of granules


Advantages and Disadvantages of Dry Granulation

There are few advantages of dry granulation over wet granulation during pharmaceutical manufacturing, as well as few disadvantages of dry granulation are also observed.


Advantages

  • Suitable for moisture sensitive APIs
  • Suitable for heat sensitive APIs
  • Less floor space
  • Less granulation time
  • Cost effective


Disadvantages

  • Specialized equipment
  • High force required
  • More dust generation
  • Not suitable for all materials

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