Preformulation Flashcards
define preformulation
first step in developing dose form by gathering information regarding drug properties which may have a bearing on product formulation
what must formulator develop in preformulation
detailed procedure and specification of API, excipients, and finished product
define organoleptic
description of drug including taste, color, and odor
how do you fix bad colors
coating or coloring agent
how do you fix bad odors
aromatic excipient or coatin
how do you fix objectional taste
flavouring agent, coating, insoluble form
what are the colors
off white
tan
cream yellow
shiny
what are the odors
pungent sulfurous fruity aromatic odorless
what are the tastes
acidic bitter bland intense sweet tasteless
what is required for metal impurities
excipients like EDTA
limit test development
what dooes micrometrics include
particle size shape and surface area
what does small particle size do
increase surface area for excipient , oxygen, and moisture
what are some problems of milling
agglomeration
polymorph formation
static electricity
what must a drug do before absorption
dissolve in GI fluids
at what solubility percent are drugs considered to not have dissolution problems
1%
what is the risk associated with HCl oral salts
common ion effect with gastric HCl
if drug not ionizable what are other means of increasing solubility
use of metastable polymorph use of complexes solid solution techniques incorporation of surfactants micronization
if dissolution rate slower than absorption what would happen if you changes the dissolution rate
it would change the absorption rate bc dissolution is the rate limiting step
what does a larger log p value indicate
more affinity for organic phase than aqueous
what are properties of crystallin sunstances
definite shape
stable
can form polymorphs
what are properties of amorphous substances
no definite shape
more soluble
better dissolution
if absorption is dissolution rate limited what might be one way to speed it up
use metastable polymorph
what are the forms of a polymorph
only one stable form and metastable forms convert over time to stable , unless in a solution it no longer differs
when can you justify use of metastable polymorph
when it exhibits sufficient chemical and physical stability
what stability studies are done on tablets
drug alone
drug with excipients
drug in solution
what factors influence stability
pka solubility melting point crystal habit/form equilibrium moisture content
what are the most common factors for instability
light
heat
oxygen
moisture
how are high humidity levels for testing achieved
using saturated solutions of various salts
what are ways to pull samples stored at elevated temperature
TLC
HPLC
DTA
what other factors are inportant to formulator
density
flow
hygroscopy
compressibility
how does density affect formulation
excipients must have similar density or segregation will occur
affects flow properties
why must moisture content be know
may affect flow and compression properties
how do flow properties affect formulation
need good flow for blending, granulation, compression
assessed by angle of repose
whats a good angle of repose
25-45
smaller = better flow
what is compressibility
powder forms hard uniform contact under moderate pressure
