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The dissolution rate of a drug substance provides insights into absorption on its own (T/F)?
False, the dissolution rate when combined with solubility, partition coefficient and pKa provide insight into its potential for absorption
What chemical forms of a drug can alter the dissolution rate?
What ways can you alter a drug chemically to alter the dissolution rate?
- Alter the form:
Which Crystal form has a greater dissolution rate?
The metastable form (compared to the stable form)
Do smaller or larger particles have a greater dissolution rate?
Why do smaller particles have a greater dissolution rate?
They have a greater surface area
What surface properties effect the dissolution rate of a drug?
A high surface energy (i.e. microionized powder may result in what two things that effect the dissolution rate?
Poor wetability and agglomeration
What is deaggregation?
The breakdown of Granules or aggregates into fine particles
What is the term for the breakdown of granules or aggregates to fine particles?
After the drug has been dissolved, what process can occur to remove it from solution?
What are the steps in the process of breaking down tablets?
Tablet to granules/aggregates to fine particles to drug in solution
What is polymorphism?
The existence of at least 2 different crystal structures of the same chemical substance
What is the term that describes at least two different crystal structures of a single chemical?
Polymorphs are different ion their crystal structures, but identical in what ways?
They liquid and vapor states
What physical differences do polymorphs have?
- melting point
- crystal shape
- optical properties
- electrical properties
- vapor pressure
Why are polymorphs important to pharmaceuticals?
They have different absorption rates and therapeutic responses
Name four examples of polymorphic drugs (as discussed in class):
- Theobromide oil
What methods are available for characterization of polymorphic drugs?
- Thermal analysis (DSC, TGA, Thermomicroscopy)
- X-ray diffractometry
Why is it important to characterize the melting point of a drug?
Helps in detection of impurities