Powders 5 Flashcards

1
Q

What are 4 factors that affect processing

A

particle size and shape
bulk density
powder flow
compressibility

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2
Q

what is density

A

volume occupied by a given mass of powder

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3
Q

why is a low bulk density a problem

A

leads to a large volume and a large tablet hence inconvenient

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4
Q

why is a range of bulk densities a bad thing

A

it would lead to a different tablet weight as well as different sizes

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5
Q

what is v true

A

the volume occupied by a powder itself with no pores

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6
Q

what is v bulk

A

the volume occupied by a powder including the pores i.e. including the empty gaps between particles known as V apparent

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7
Q

what is vbulk equal to

A

v true + v pores

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8
Q

what is packing fraction equal too

A

bulk density vs true bulk

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9
Q

how do we calculate bulk density

A

mass / bulk volume

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10
Q

how do we calculate true density

A

mass / true volume

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11
Q

what is porosity

A

void space of the powder bed

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12
Q

how do we calculate porosity

A

[1 - (vtrue/vbulk) ] x 100

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13
Q

what is an excipient

A

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

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14
Q

why use excipients

A

to ensure tablet manufacturing runs smoothly and that the produced tablets are of satisfactory quality

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15
Q

What are the x type of excipients

A
filler
binder
disintegrant
glidants
lubricant
colourants
flavouring agents 
sorbents
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16
Q

what is a filler

A

used to give necessary bulk of the formulation

17
Q

what are the requirements of a filler

A

chemically inert
non hygroscopic
appropriate technical properties
biocompatibility

18
Q

what is a binder

A

promote adhesion of the particles ensuring the required mechanical strength

19
Q

what is a disintegrant

A

promote tablet breakage into smaller particles after admission

20
Q

what is a glidant

A

glidants improve flowability by reducing frictions between particles

21
Q

what is lubricant

A

reduce the frictions between particles and the die walls as a result the powder flowability is improved

22
Q

what considerations should we make when choosing a lubricant

A

where is the lubricant likely to be found within the granule

what happens if you over or under lubricate

23
Q

what is the aim of mixing

A

obtain a homogenous distribution of two or more components

24
Q

what is segregation

A

opposite of mixing

25
Q

what are 3 consequences of segregation

A

difference in

density
shapes
sizes