Oral formulations: crystals preformulation & powders 2

Question 1

What are the 3 testing techniques used to test crystallisation?

Answer 1

x - ray diffraction
DSC - differential scanning calorimetry
optical, polarised light

Question 2

What is Bragg’s law?

Answer 2

diffracted intensities are at max when the relationship between wavelength & spacing between objects is: wavelength = 2dsin(theta)
d= spacing between objects
theta = half of diffraction angle

Question 3

What are the two methods of how DSC works?

Answer 3

same energy input, measure temp differences

maintain same heating rate for both samples, measures energy required

Question 4

What occurs when crystals which are not cubic exhibit birefringence?

Answer 4

can be seen through crossed polars

Question 5

What can impurities cause?

Answer 5

instability, poor appearance and toxicity

Question 6

Why is solubility analysed during preformulation?

Answer 6

bioavailability
design of delivery system
design of purification methods

Question 7

What sort of parameter is solubility?

Answer 7

thermodynamic