PHA 327 - Exam 2 - Tablets 3
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What method of compression creates the most stable form of tablets?
What are the limitations of Direct compression?
- Differences in particle size may lead to segregation in the hopper
- Low dose drugs may not be uniformly blended
- Unsuitable for High dose drugs with poor flow and compressibility
The granules used for tablet compression must have what characteristics?
- Have good low properties
- Be compressible
- Have lubricant properties
During what step of tablet compression is it most important to have granules with lubrication properties?
The ejection of the tablet
Describe dry granulation:
- compact the components of the tablet with a tablet press
- Mill the compact to obtain the granules
What are the advantages of dry granulation?
- No need to dry
- Binder solutions not needed
- Good for moisture sensitive materials (i.e. aspirin and effervescent tablets)
What are some disadvantages of dry granulation?
- Requires a very heavy duty press
- Does not permit uniform color distribution
Name two drugs that are moisture sensitive (as discussed in class):
- Effervescent drugs
Describe wet granulation:
liquid is added to a powder with agitation to produce agglomeration or granules
What is the oldest and most conventional way of making tablets?
What are the advantages of wet granulation?
- Modifies properties of the formulation to overcome tableting deficiencies
- Improved compressibility = lower pressure in the tablet press
- Better content uniformity (especially in low doses)
- Segregation of components is prevented
- The dissolution rate of an insoluble drug may be improved
Why are granules beneficial for producing compressed tablets?
They have better flow properties and improved compressibility
What characteristic of granules improves their compressibility?
fracturing during compression, exposing new surface areas
Why do granules have better flow properties that powders?
Granules are more spherical
What type of granulation is preferred for compression of large dose drugs?
What are the limitations of Wet granulation?
- Not good for moisture or heat sensitive drugs
- Migration of material to the surface of granules may occur
- Incompatibilities between contents will be aggravated
- Multiple transfer steps increases material loss
Which type of tablet manufacturing process has the least number of steps?
Which type of tablet manufacturing has the most number of steps?
What is tablet lamination?
Separation of the tablet into two of more layers
What is the term for the separating the tablet into two or more layers?
What is the term for partial or incomplete separation of the top or bottom layer of a tablet?
What is capping?
partial or complete separation of the top or bottom layer of a tablet from the main body
What causes capping of tablets?
- Air trapped in granules
- Improper setting of tablet press
- Die wall pressures exceed the elastic recovery
How do you fix Capping and Lamination of tablets?
- Change procedure
- Increase the binder
- Increase/change the lubricant
- Add dry binder
- Use tapered dies
Changing the procedure, increasing the binder, adding dry binder, increasing the lubricant and using tapered dies are all remedies for what issue?
Capping or Laminating
What is picking?
A form of sticking where a small portion of the tablet remains on the punch face
What is sticking?
tablet materials adhering to the die walls
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