Preformations

Question 1

Properties of an API:

Answer 1

1. Organoleptic properties
2. Purity
3. Micromeretics
4. Solubility
5. Dissolution/absorption
6. Crystal properties & polymorphism
7. Stability
8. Miscellaneous

Question 2

What are organoleptic properties?

Answer 2

description of drug substance incl:
- COLOUR (can add colouring agent or coat tablets)

• ODOR (contain by coating or include an aromatic excipient)
• TASTE (masked by flavouring agent, coating or use of an insoluble salt form)

Question 3

Bitter:

Answer 3

AMINE group (ex: alkaloid groups)

Question 4

Sour:

Answer 4

ACIDS (ex: citric acid)

Question 5

Sweet:

Answer 5

HYDROXY groups (ex: glycerol & sugars)

Question 6

Salty:

Answer 6

INORGANIC SALTS (ex: NaCl & KCl)

Question 7

Umani:

Answer 7

~ AA’s (ex: glutamate)

Question 8

What is purity?

Answer 8

trace amounts of metals may affect stability & ~ impurities may be toxic
- may req. addition of excipients (ex: EDTA) OR limit test dev.

Question 9

What are micromeretics?

Answer 9

particle size, shape & SA of drug material (may affect dissolution)
*- small particle size will INCREASE SA

Question 10

What is solubility?

Answer 10

product must dissolve in GI fluids prior to absorption
*- better dissolution, better bioavail.
- drugs w/ solubility >1% are good
- may include use of metastable properties

Question 11

What is dissolution/absorption?

Answer 11

*-if Kd slower than Ka, dissolution is RLS & change in Kd will affect absorption rate

*- if absorption rate (Ka) is slower than Kd, Ka is the RLS

P = [organic]/[Aq]
*- larger value, more affinity for organic phase

Question 12

What is dissolution/absorption?

Answer 12

*-if Kd slower than Ka, dissolution is RLS & change in Kd will affect absorption rate

*- if absorption rate (Ka) is slwoer than Kd, Ka is the RLS

P = [organic]/[Aq]
*- larger value, more affinity for organic phase

Question 13

What is crystal properties & polymorphism?

Answer 13

• amorphous form more soluble & shows better bioavail, but crystalline is often more stable

Question 14

Polymorphism:

Answer 14

drugs which exist in crystalline form may be able to form diff types of crystals = AKA polymorphism

only 1 form is stable & the others (metastable) forms will convert over time to the stable form

once in solution, the forms no longer diff

must ensure that processing does not cause a transition
- reported after milling, granulation, drying & compression

Question 15

What is stability?

Answer 15

pKA, solubility, MP, crystal habit & form, & equil moisture content all influence stability

most common environmental factors for instability are: light, heat, O2 & moisture

Question 16

What are the miscellaneous?

Answer 16

• Density - affects flow properties
• Hygroscopicity
• Flow properties
• Compressibility