Powders 5 Flashcards
What are 4 factors that affect processing
particle size and shape
bulk density
powder flow
compressibility
what is density
volume occupied by a given mass of powder
why is a low bulk density a problem
leads to a large volume and a large tablet hence inconvenient
why is a range of bulk densities a bad thing
it would lead to a different tablet weight as well as different sizes
what is v true
the volume occupied by a powder itself with no pores
what is v bulk
the volume occupied by a powder including the pores i.e. including the empty gaps between particles known as V apparent
what is vbulk equal to
v true + v pores
what is packing fraction equal too
bulk density vs true bulk
how do we calculate bulk density
mass / bulk volume
how do we calculate true density
mass / true volume
what is porosity
void space of the powder bed
how do we calculate porosity
[1 - (vtrue/vbulk) ] x 100
what is an excipient
excipients are pharmacologically inert materials which are added to pharmaceutical dosage forms to improve their characteristics.
though inert they might affect the bioavailability of the active ingredient
why use excipients
to ensure tablet manufacturing runs smoothly and that the produced tablets are of satisfactory quality
What are the x type of excipients
filler binder disintegrant glidants lubricant colourants flavouring agents sorbents
what is a filler
used to give necessary bulk of the formulation
what are the requirements of a filler
chemically inert
non hygroscopic
appropriate technical properties
biocompatibility
what is a binder
promote adhesion of the particles ensuring the required mechanical strength
what is a disintegrant
promote tablet breakage into smaller particles after admission
what is a glidant
glidants improve flowability by reducing frictions between particles
what is lubricant
reduce the frictions between particles and the die walls as a result the powder flowability is improved
what considerations should we make when choosing a lubricant
where is the lubricant likely to be found within the granule
what happens if you over or under lubricate
what is the aim of mixing
obtain a homogenous distribution of two or more components
what is segregation
opposite of mixing
what are 3 consequences of segregation
difference in
density
shapes
sizes
