What is the general definition of granulation in pharmaceutical powder processing?
The process of size enlargement of powders.
In the granulation process, what is the stage immediately following the formation of granules?
Sieving into microionised granules.
How does granulation help prevent segregation of a drug and its excipients?
It increases the uniformity of the mixture by controlling the size distribution.
Why do fine particles typically exhibit poor flow properties?
They are naturally adhesive and cohesive.
What is a primary manufacturing consequence of poor powder flow during tableting?
Inconsistent capsule filling or poor tableting quality.
How does granulation benefit slightly hygroscopic materials?
It helps prevent the absorption of moisture.
Why does granulation lead to the production of stronger tablets?
Granules are easier to deform or fragment, which improves compressibility.
How is the densification of powder defined during the granulation process?
Granules occupy less volume per unit weight compared to the parent powder.
What safety risk is reduced by the densification of pharmaceutical powders?
Dust hazards, such as toxicity or explosive potential (flour analogy).
How does granulation improve the wettability of hydrophobic drugs?
By mixing the hydrophobic drug with hydrophilic excipients.
What is the acceptable range for moisture content in granules intended for tableting?
$3-5\%$
What is the maximum allowable weight percentage of ‘fines’ in a granule batch for tableting?
$10\% w/w$
Besides moisture and flow, what three physical appearance properties are required for granules?
Shape, size, and color.
What type of particle size distribution is required for granules used in capsules?
A narrow particle size distribution.
Which granulation method involves mixing powder with a binder liquid to create a wet mass?
Wet granulation.
What is the first step in the mechanism of wet granulation?
Nucleation.
During the nucleation step of granulation, what state is formed when particles first combine with liquid?
The capillary state.
What occurs during the ‘transition growth’ phase of granulation?
Nuclei grow by adding single particles or combining with other nuclei.
What is the consequence of allowing the granulation process to proceed too long in ‘ball growth’?
Particles become too large and spherical.
In the wetting process, liquid bridges are converted into solid bridges through the process of _____.
Crystallization
Under what condition can a solid bridge form in wet granulation without the addition of a specific binder?
When the powder partially dissolves and then crystallizes upon drying.
Which granulation method relies on high power to push particles together for adhesion?
Dry granulation.
What physical force is responsible for adhesion during dry granulation?
Short-range van der Waals forces.
Rank the three states of bridge formation in dry granulation from weakest to strongest.
Pendular $<$ Funicular $<$ Capillary.
