4 - Preformulation Flashcards
Preformulation
gathering info regarding drug properties which may have a bearing on product formulation
What are organoleptic properties?
Description of drug substance including:
color
odor
taste
Organoleptic properties:
How do you fix objectionable colours?
- colouring agent may be included
- tablets may be coated
Organoleptic properties:
How do you fix objectionable odors?
- contain the odor in a coating
- inclusion of an aromatic excipient
Organoleptic properties:
How do you fix objectionable taste?
- masked by flavoring agent, coating
- use of an insoluble salt form
5 tastes recognized
bitter sour sweet salty umami (protein taste)
Bitter taste is associated with ____ groups
amine
Sour taste associated with ____
acids
Sweet taste associated with ____ groups
hydroxyl
Salty taste associated with _____ ____
inorganic salts
Umami associated with some ____ ___
amino acids
What are micromeretics?
particle size
shape
surface area
_____ crosses membranes better
unionized
_____ dissolves better
ionized
What is the formula for partition coefficient?
P = [organic]/[aqueous]
often expressed as log P
larger P value means?
it has more affinity for the organic phase
smaller P value means?
it has more affinity for the aqueous phase
What is a Franz cell used for?
measure passive diffusion through membrane
sample how much drug has crossed the membrane
Generally _____ form is more soluble
amorphous
more soluble that identifiable definite shape
When is a polymorph transformation reported?
after milling, granulation, drying and compression
Granulation can also cause the formation of?
solvates or hydrates
Drying may cause transformation to ??
anhydrous crystalline or amorphous forms
Properties that influence stability
pKa solubility melting point crystal habit and form equilibrium moisture content
Most common factors for instability are ?
light
heat
oxygen
moisture
Data is analyzed using ___
MLR
multiple linear regression
In the presence of moisture many drugs ?
hydrolyze
react with excipients
oxidize
How do you measure how moisture affects certain drugs?
- keep constant temperature
- measure different samples and different humidity levels
Other factors important to the formulator are?
density
hygroscopicity
flow properties
compressibility
Density
- provide a rough idea of the size of the finished product
- density affects flow properties
Hygroscopicity
- moisture content
- can affect flow and compression properties
Flow properties
- good flow properties essential for blending, granulation and compression
- angle of repose measures flow (prefer angle between 25 and 45 degrees)
