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Clare's lectures semester 2 > Granulation > Flashcards

Granulation Flashcards

1
Q

What is trajectory segregation?

A

When larger particles travel greater horizontal distances than smaller particles

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2
Q

What is Elutriation segregation?

A

When very small particles sediment on top of the larger particles

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3
Q

What is percolation segregation?

A

Smaller particles drop to the bottom of the powder bed (as in hopper where movement of particles can take place)

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4
Q

Dense particles have the tendency to move to the bottom. TRUE OR FALSE?

A

TRUE

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5
Q

Dense particles have greater mass than less dense particles. TRUE OR FALSE?

A

TRUE

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6
Q

What are the reasons for granulation?

A
  • To help improve powder flow (increase particle size)
  • Help provide a uniform mix of powders
  • To increase density of the powder mix
  • To reduce risks of dust generation
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7
Q

What are the reasons for granulation?

A
  • To help improve powder flow (increase particle size)
  • Help provide a uniform mix of powders
  • To increase density of the powder mix
  • To reduce risks of dust generation
  • Reduce risk of caking of hygroscopic powder
  • As a dosage form
  • As an intermediate for tableting
  • Help compaction of powder mix
  • Aid wetting of particles
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8
Q

What are the factors you need to consider with granulation?

A
  • Mixing of powder granule formation
  • Segregation of constituents after mixing
  • Segregation of constituents after granule formation
  • Size distribution of granules
  • Tabletting and capsulation
  • Accurate proportions of active ingredients and excipients
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9
Q

What components does a granulating fluids have?

A
  • Solvent e.g water
  • needs to compatible
  • nees to be non toxic
  • needs to be removable by drying
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10
Q

What is a binder used for?

A

-To help particles to adhere together after drying

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11
Q

What are the different states formed during wet granulation?

A
  • Pendular state
  • Funicular state
  • Capillary state
  • Droplet state
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12
Q

What occurs in Pendular state?

A
  • Low liquid levels, discrete liquid bridges at points of contact between particles
  • Assumption that there is a uniform distribution of liquid throughout powder bed
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13
Q

What occurs in Funicular state?

A
  • Further liquid content, pendular bonds coalesce and liquid bridges form between non-touching points
  • Dependant on degree of liquid saturation, usually 25-80%
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14
Q

What occurs in Capillary state?

A
  • Liquid saturation is greater than 80%
  • Granule becomes paste like and unsuitable for wet sieving
  • Tensile strength of granule increases by 3 between pendular and capillary state
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15
Q

What is the nature and extent of liquid bridges dependant on?

A

-The amount of liquid added and method of wet massing

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16
Q

How many stages occur in bridge formation?

A

4

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17
Q

Agglomerates constantly formed and destroyed? TRUE OR FALSE?

A

TRUE

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18
Q

In dry method particle adhesion takes place due to pressure. TRUE OR FALSE?

A

TRUE

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19
Q

In wet granulation particles adhere because of liquid. TRUE OR FALSE?

A

TRUE

20
Q

What are the three phases of agglomeration?

A
  • Nucleation
  • Transition
  • Ball growth
21
Q

What occurs in Nucleation?

A
  • Partcle-particle contact and formation of liquid bridges

- Further agitation densifies pendular state which acts as a nuclei for further granule growth

22
Q

What occurs in Transition?

A
  • Nuclei can grow by single particles added via pendular bridges or wto or more nuclei can combine
  • Wide size distribution exhibited
23
Q

What is Ball growth?

A
  • Further granule growth produces large spherical granules with size increasing over time
  • Aggitation stopped (which would promote further coalescence making over massed particles)
24
Q

Pressures used in dry granulation may cause melting of low melting point materials. TRUE OR FALSE?

A

TRUE

25
Q

What method is used to help bond particles together when pressure is relieved?

A

Crystallisation

26
Q

Binders used in granulating fluid hardern or crystallise on drying. TRUE OR FALSE?

A

TRUE

27
Q

Give examples of hardening binders

A

synthetic polymers and pre-gelatinised starch

28
Q

Slower drying times result in larger crystals. TRUR OR FALSE?

A

TRUE

29
Q

What are the advantages of wet granulation?

A
  • Reduced segregation of formulation components during storage/processing
  • useful for formualtion of tablets with low active ingredients concentration
  • uses conventional excipients
  • can be post-processed (tablet coating)
30
Q

What are the disadvantages of wet granulation?

A
  • Several processing steps needed

- Solvents used in process lead to concerns e.g stability of drugs, toxicology of formulation

31
Q

Dry granulation is suitable for what types of formulation?

A
  • When product is moisture sensitive
  • When drug is heat sensitive
  • When there is poor compression exhibited after wet granulation
32
Q

What is slugging?

A

-Process used to compress dry powders into a large oversized tablet

33
Q

In slugging, binder can be used to improve bonding strength in compaction. TRUE OR FALSE?

A

TRUE

34
Q

In slugging, disintergrants can be used as excipients and labricant can be added to prevent compacts sticking to the punches and die. TRUE OR FALSE?

A

TRUE

35
Q

In slugging, disintergrants can be used as excipients and lubricant can be added to prevent compacts sticking to the punches and die. TRUE OR FALSE?

A

TRUE

36
Q

Roller compaction requires less lubricant than for slugging. TRUR OR FALSE?

A

TRUE

37
Q

Give examples of excipients used in roller compaction?

A
  • Diluent - bulks up powder mix
  • Disintergrant - to break up granule/tablet in solution
  • Binders- binds constituents together
  • Lubricant- e.g stearates
  • Glidant - anti-adherent properties
38
Q

What are the advantages for dry granulation?

A
  • Both roller compaction and slugging require conventional excipients
  • Methods not commonly associated with degradation/ alteration of drug method during processing
  • No heat or solvents required
39
Q

What are the disadvantages of dry granulation?

A

-Roller compaction requires specialist equipment
-segregation of components may occur post processing
may be issues regarding powder flow
-Final tablets usually softer than with wet granulation

40
Q

Give example sof granulating agents

A
  • HPMC
  • MC
  • ACACIA
  • PVP
  • PRE-GELATINISED STARCH
41
Q

What is spheronisation?

A

-Form of granulation which forms unform sized spherical pellets

42
Q

when is spheronisation used?

A

-when spheres required as dosage form

43
Q

spheronisation is more labour intensive than other forms of granulation. TRUE OR FALSE?

A

TRUE

44
Q

Wet massing is important to produce good quality speheres. TRUE OR FALSE?

A

TRUE

45
Q

What are the stages of spheronisation?

A

Mixing - Wet massing - Extrusion - Spheronisation - Drying - Screening

46
Q

Water level is not critical for optmising the spheronisation process. TRUE OR FALSE?

A

FALSE

Clare's lectures semester 2 (10 decks)

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