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Manufacturing > A2 RCDG > Flashcards

A2 RCDG Flashcards

1
Q

How does RCDG works?

A

consolidation and densification of the material in between two pressure rolls

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2
Q

What are the units of RCDG

A

Feeding, compaction and granulation unit

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3
Q

The aim of RCDG

A 
increase of particle size
decrease amount of fines
increase bulk density
, better flowability
decrease of demixing
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4
Q

what are the main region in RCDG (learn to draw it)

A

Slip, nip and release region

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5
Q

what happend at the slip region?

A

Velocity of the feeding material is samller compred to the movement of the rolls

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6
Q

where is a density gradient formed

A

at the slip region

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7
Q

what does a density gradient mean?

A

the lower the powder get into th nip region, the higher the density

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8
Q

nip region

A

Material and roll speed are moving at the same space

decreas of the gap width, which significantly increase the roll pressure

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9
Q

why do densification occur at the nip region?

A

due to the decrease roll gap (Gap width)

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10
Q

what is the densification factor?

A

nip width /gap width

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11
Q

what happend when the gap width decrease

A

the compaction force increases

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12
Q

what influence the ribbons density?

A

SCF
Gap width
excipients

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13
Q

Release region

A

Increase of the Gap width

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14
Q

On what does the release depends?

A

On the stored elastic strains on the compact

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15
Q

What happend when the ribbons are release?

A

the density decrease due to elastic strain of the compact

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16
Q

What are the roll compaction design

A

Fixed gap and the flexible gap

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17
Q

Fixed gap

A

Both rolls have a fixed position

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18
Q

what is the main disad von the fixed gap?

A

Fluctuation of material during feeding, leading to different solid fraction

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19
Q

How does the SF affect CF in a fixed gap?

A

a high amount of powder, leads to high SF. the increase of the SF, increases as well the CF, more dense ribbons

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20
Q

How does the Cf affects the granules?

A

high CF results to larger granules

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21
Q

Probleme in the fixed gap

A

high fluctuation of feeding–> different solid fraction–> compaction force cannot be kept constant–> ribbons with different density

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22
Q

why it is important to keep the SF constant

A

due to the direct relation to the CF, if Sf changes, the Cf changes as well

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23
Q

How can the Cf be adjusted in the fixed gap

A

just by the feeding screw speed

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24
Q

flexible gap

A

fixed master roll, slave roll (movable)

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25
Q

what is the ad of the flexible gap over the fixed gap

A

Cf can be kept constant, indenpendly of SF

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26
Q

How is CF kept constant in th flexible gap?

A

it is kept constant due to constant opening of the moveable rolls

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27
Q

How can the CF be controlled?

A

by the SFS and RS

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28
Q

How can the solid fraction be controlled

A

By keeping the RCF Constant

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29
Q

Parameter that influences compaction

A

specific compaction force
Gap width
Roll speed

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30
Q

What is the specific compaction force?

A

it is the compaction force per cm of roll width

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31
Q

what should be kept constant during scale up

A

the SCF and the GW

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32
Q

What is the unit of SCF

A

CF/RW [KN/cm)

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33
Q

the SFC depends on

A

Cf and RW

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34
Q

Why should SCF and GW be kept constant?

A

in order to achieve a uniform ribbons property.

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35
Q

What affect the ribbons density

A

SCF and GW

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36
Q

What’s the main different between the manual and automatic production mode, regarding the CF and GW

A

Manual: just the CF is kept constant
automatic: both CF and GW are constant

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37
Q

How is the SCF kept constant in the manaul mode?

A

by hydraulic cyclinders or by spindel motor

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38
Q

How is the GW kept constant in the manaul mode?

A

by a control of the circuit varying the speed of tamping augur

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39
Q

what happend to CF, if the GW changes?

A

GW decrease–> increase of Cf

GW increase–>CF decrease

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40
Q

for what is the roller orientation important

A

for bypass

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41
Q

Which orientation is possible?

A

Horizonal, Vertical

inclined

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42
Q

Horizontal feeding?

A

by gravity, high bypass, material remaining in nip region

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43
Q

vertical alignment?

A

No gravitational forces, less bypass

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44
Q

inclined alignment

A

decrease of bypass

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45
Q

Feefing system and their function

A

feed auger–> defines the FR

tamp auger–> transport to the gap and predensification

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46
Q

how should the ratio temp auger speed to feed auger speed should be?

A

> 1

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47
Q

Roll surface

A

smooth, knured

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48
Q

what are roll surface use for?

A

Use to maintain the back pressure

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49
Q

Back pressue is important for?

A

to avoid bypass

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50
Q

How can bypass be avoided?

A

Vertical feeding system or using a rough surface

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51
Q

How does the roll surface influence the ribbons?

A

smooth roll surfaces–> higher density of the ribbons

rough roll surfaces–> thickness of ribbons

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52
Q

Types of sealing system

A

Cheek plates

Rim roll

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53
Q

Advantage of rim roll over cheek plates

A

more homogeneous ribbons density distribution in the RR sealing system than in the cheek plates

54
Q

Why are rough surface important?

A

they are important to increase friction for better feeding and so increase of the nip region

55
Q

what is important during feeding of the material?

A

Feeding should be uniform to avoid
poor compact quality
generation of excess fines
more un-compacted material

56
Q

When can the gravity feeding be used?

A

when the powder is dense and free flowing

57
Q

Why is the screw feeder better than the gravity feeder?

A

it provides a pre-compression force

58
Q

What does the froce in screw feeder does?

A

it increases the friction between powder and the roll surfaces to improve compaction

59
Q

what happend when we have a lot of bypass

A

it causes segregation of blend and consequently content uniformity

60
Q

the gap size influence?

A

the density profile of the ribbons

61
Q

What cause gap size variation?

A

Nono-free-flowing powder and changes in the powder density

62
Q

why it is important to have a constanst CF?

A

to have a uniform ribbon thickness with a uniform distribution of the density

63
Q

Material properties have impact on?

A 
Compaction properties of ribbons
granules PSD
flowability,
content uniformity
compaction properties of the tablets
64
Q

What influence the porosity of the ribbons

A 
RCDG process (FSS, RS, RP, RG)
milling conditions
65
Q

under feeding or over feeing leads to?

A

under feeding–> less compaction

over feeding–> over compaction

66
Q

What happend if there is more entrapped air during feeding?

A

it results in lower bulk density and higher porosity

67
Q

the roll speed is characteris by what?

A

the dwell time of the material between the rolls

68
Q

high rolls speed results to?

A

it reduces compaction, therefore the dwell time

69
Q

what is the consequences of a short dwell time?

A

short dwell time reduces tome for plastic rearrangemnet and bonding, ribbons with low density

70
Q

long dwell time is achieve by?

A

reduction of the roll speed, therefore particle have more tome for rearrangement, ribbons with higher density

71
Q

how does a high Cf influence the PS of the granules

A

higher compaction force produces more dense ribbons, larger granules PS

72
Q

Cf depends on?

A

FSS and RS

73
Q

higher Cf is obtained by?

A

decrease of the RS and increase of the FSS

74
Q

Decrease of the ribbons porosity is cause by?

A

decrease RS and higher FSS

75
Q

increase Ribbons porosity

A

increase of RS (shiort dwell time) and slow FSS (less powder material)

76
Q

Granule size enlargementz

A

larger partciles always resulus in lower tabletability

77
Q

the quality of the granules are influence by?

A

by the porosity distribution if the roller compated ribbons

78
Q

How can the strength of the ribbons been describe?

A

through the density of the ribbons

79
Q

how does a variation of the porosity influences the properties of the granules?

A

it influences the PSD and density of the granules

80
Q

PSD of the granules depends on?

A

excipeints and ribbons porosity

81
Q

What’s the main different between brittel and plastic material?

A

Brittel material breaks easily and so independ of the compaction force

plastic material depends on the compaction force

82
Q

what happend to plastic material at high CF

A

by high CF, longer dwell time –> ribbons with high density

83
Q

Plastic material at high CF

A

dense ribbons–> broad PSD granules–> less binding capacity during tableting

84
Q

Relation between ribbons and tablets?

A

denser ribbons leads to denser granules, making tablets more porous

85
Q

Granules size is affect by?

A

infleunces by the degree of strenght reduction after dry granulation for plastcially deforming material

brittel material are unaffected

86
Q

granules hardening?

A

due to precompression to form the granules, the

87
Q

granules hardening?

A

due to precompression to form the granules, the crystal can not undergo futher compaction process

88
Q

tablet behaviour after roll compaction

A

improved die filling, mass uniformity, less deaeration and capping

89
Q

which tablet properties are most affect after granulation

A

lower compressibility, compactability and tabletability

90
Q

Why do granules products porous tablets?

A

due to higher bulk density

reduce compactability and compressibility and low tabletability

91
Q

Tabletability (know how to draw the diagram)

A

Capacity of a powder to be transformed into tablets of specificed strength under the effect of CF
TS against SF

92
Q

Compactibility

A

is ability of a powdered material to be transformed into tablets with strength during densification
TS aginst SF

93
Q

Compressibility

A

Reduction of volume wuth applied CP

SF gainst CP

94
Q

compactibility is related to?

A

Bulk density and properties of the material

95
Q

lubrication is important for?

A

Decrease friction during compression of the powder

96
Q

Less friction during tabletting is achieve by

A

external lubrication

97
Q

Which material is sensitive to lubricant

A

Plastic materials

98
Q

Tablets with high TS are obtained when in RCDG

A

by low CF, leading to porous ribbons, poros granules, high TS due to increase compactibility

99
Q

Name some dry binder

A

MC, HPC, HPMC, PVP

100
Q

How can the RA be divided?

A

steps to identify, analyse or prevent possible failures or reduce their risk

101
Q

Risk identification

A

Systematically uses information to identify possible hazards

102
Q

Risk analysis?

A

investigates the likelihood or probability of occurrence, the severtity and the detectability using a Failure Mode and Effects Analysis (FMEA) or Hazard Analysis of critical control points (HACCP)

103
Q

Why do we used risk control

A

to keep the risk as low as possible

104
Q

what is a part of a risk control

A

mitigation or detection

105
Q

mitigation?

A

it reduces the serverity or the lekelihood of occurrence by modification of the process or single process steps

106
Q

detection

A

reduces the severity and occurrence probability by additional conctrols

107
Q

What is the output of a RA

A

it is either nummerical probability (quantitative estimate) or risk description by precisely definded scores (qualitative exstimte)

108
Q

Laser diffraction

A

encountered of the paticles by laser beam, leading to diffraction in a specific angle

109
Q

What is the Fraunhofer theory?

A

If the particles are larger than the wevelength of the light, the monochramatic light is scattered forward with a small angle change

110
Q

Mie theory

A

if the particles are smaller and reach the dimension of wavelength

111
Q

what is required to calculted the Mie theory?

A

optical properties of the disperion medium and the dispered particles (absorbtion refraction index)

112
Q

How can one divide samples for analysis?

A

by using a sample divider

113
Q

what is the mean median diameter?

A

the size of particles at which 50 % of the sample is smaller and 50 % is larger than this size

114
Q

what is a ishikawa diagram

A

a diagram which shows possible causes for an effect or probleme

115
Q

How can one divide the ishikawa diagram?

A

Machine, Method, Material, Manpower, Measuremnet and Mother Nature

116
Q

How is the risk prority number calculted?

A

RPN= S* P* D

117
Q

increase milling speed on the granules?

A

finer granules, due to a higher shear stress during the process

118
Q

why do the sieve size influence the particle size?

A

both are directled related, an increase should lead to coarser granules, while lower mesh sizes will results in smaller granules

119
Q

How ths linear model investigated?

A

with a leinear regression (Q-q plot of the standardized residuals)

120
Q

what is used to to describes the fit of the values?

A

the coefficient of determination

121
Q

Why do we used the R2 adjust

A

incases of a low sample size or a high number of coefficient

122
Q

Which two parameter are most siginicant for the PSD

A

SS and CF

123
Q

FFD are used for , whiled CFD are used for?

A

FFD, for main effects and interactions, whereby CCD are use to define the design space

124
Q

attributes of excipients to be investigated?

A

densit, PSD, flowability, porosity

125
Q

in which order do we run the DoE

A

in a randomized order , in order to transfer the systematic erre into randm error

126
Q

what influences most the fraction on fines during granulation

A

compaction force and not the milling speed, eventhough a higher milling speed results to higher fractions of fines

127
Q

why do we have a low TS when lubricate external than internal

A

internaly lubrication leads to the decrease of the bounding strength of the particle, due to the hydrophobic film formed during compression

128
Q

how do the brittel material affects t he compactability

A

it increases the compactability, due to their easy breakage during tablet compression

129
Q

where is the formation of the hydrophobic filmer higher?

A

by the external lubrication

130
Q

why do granules product porous tablets?

A

due to granules entlargment and the granules hardening, it decrease the interlocking of the particles during compression
means, granules have low compactability and compressibility

Manufacturing (7 decks)

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