As compaction force increases, contact area between particles increases, particle deformation starts to occur. Elastic deformation: granules attempt to return to their original shape or form after stress is released. Plastic deformation: granules do not totally recover after stress is released. Fragmentation occurs when compaction force continues to increase Particles fracture, create multiple new surface sites, additional contact points and potential bonding sites.
Particle Bonding:
Process of dry granulation relies on inter‐particulate bond formation. Under compaction or high pressure, bonding force between the particles develops by the direct contact between the solid surfaces.
The particles can …show more content…
Direct Compression:
Suitable for formulation with high drug loading yet good flowability. Excipients and API are first blended in a intermediate bulk container. The blend is then fed directly to the tablet press. Segregation is often the main issue that needs to be addressed, due to:
– drastic differences in the characteristics of the ingredients used
– “drop height”: distance between the outlet of the container and the surface where the powder comes to rest
Finished Granules will be sent to the quality control lab for testing such as moisture and assay testing.
• Tabletting
The process by which force is applied to a volume of loosely dispersed powder or granules, compacting and solidifying the loose particles into a well‐defined shape. When the force is applied, the void spaces between the particles are reduced, the particles are brought closer to each other and bonds are formed between particles. These inter‐ particle bonds provide coherency to the powder allowing the powder to form a compact.
4 Main stages of tableting …show more content…
-Film coating involves the deposition of a thin film of polymer surrounding the tablet core
It involves the conversion of a viscous liquid into a visco‐ elastic solid as a result of continual solvent evaporation
Reasons for coating tablets:
¥ To protect tablet core from environment (e.g. light or moisture)
¥ To mask bitter / unpleasant taste of API in the tablet
¥ To facilitate ingestion of the tablets
¥ To improve appearance of tablets
¥ To improve mechanical strength of tablets, reducing ‘dusting’
¥ To differentiate between Products
¥ To provide functional coating
- Delayed release (enteric)
- Controlled release (extended)
- API coating (precision)
Film coating is by spraying a layer of coat. Enteric coating purpose is to increase the timing for disintegration (so that the drug can bypass the first metabolism and into the blood stream of the user). Enteric coating should withstand 2 hours in acidic environment like in the stomach and dissolve fast in alkaline environment like in the intestine. Sugar coating is to mask the taste of the tablet.
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