Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHARM 125 Midterm 1 > Coating > Flashcards

Coating Flashcards

1
Q

Why do we coat tablets?

A
  • To mask unpleasant taste/odour
  • To protect drug from inactivation in gastric fluids (enteric coating)
  • Minimize irritation (GI mucosa)
  • To improve mechanical strength and flow
  • Reduce interaction
  • To modify drug release properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the types of tablet coating?

A
  1. Sugar coating
  2. Film coating
  3. Press coating
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the sugar coating steps (7)

A
  1. Sealing
  2. Subcoating
  3. Coating
  4. Colouring
  5. Smoothing
  6. Polishing
  7. Printing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the sealing step in sugar coating
Ex.

A
  • application of polymer coating to tablet core to protect from moisture, light, oxidation
    Ex. Shellac, Cellulose acetate phthalate (CAP), Polyvinyl acetate phthalate (PVAP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the subcoating step & coating in sugar coating

A

Subcoating
- improves mechanical strength of tablet and protect against moisture
- subcoating syrup and powder in 3-8 layers

Coating
- gives 30-50% weight increase
- coating Syrup and powder up to 40 layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When is colouring step in sugar coating

A
  • usually with the last coating layer
    Ex. water-soluble dyes or water-insoluble pigments
    (titanium dioxide, iron oxide)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is added in the smoothing step in sugar coating

A

add a simple syrup solution
- contain a low % of titanium dioxide
- approx. 60-70% sugar solids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the polishing step in sugar coating
ex?

A

gives the glossy finish to tablets
- wax mixtures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the printing step in sugar coating

A

can be done before or after polishing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are some problems with sugar coating?

A
  • breakage of tablets during tumbling process
  • non-uniform coating due to poor mixing
  • twinning (tablets sticking together) due to improper drying before the application
  • Colour migration (mottling) during drying when water-soluble dyes are used
  • Cracks and fissures from permeation of moisture into core
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe film coating in general

A
  • involves adding a thin, uniform polymer coating onto the surface of tablets, capsules, multiparticulates (pellets)
  • Minimal weight increase (5%)
  • significant reduction in processing time
  • provide multiple options to modify release of drug
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 6 components in a film coating formulation?

A
  1. Polymers
  2. Solvents
  3. Plasticizer
  4. Colouring agents
  5. Anti-adherents
  6. Surfactants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 2 types of polymers in film coating formulation? which are functional vs non-functional

A

Immediate release (non-functional)
Modified release (functional)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are examples of immediate-release coating?

A
  1. Cellulose derivatives
    - hypromellose or HPMC
    - Hydroxypropyl cellulose

2 .Vinyl derivatives
- Polyvinyl alcohol

  1. Acrylic derivatives
    - Methylmethacrylate copolymers
    - methacrylic acid copolymers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Explain delayed release

A
  • designed to prevent release in the upper part of the GI tract
  • known as enteric coatings or gastroresistant coatings (protect drug & minimize irritation from stomach)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What pH do most effective polymers have for enteric coatings (delayed release)

A

pH 5-6

17
Q

Delayed release coating polymers examples

A

see one note

18
Q

Explain the polymers of EXTENDED-release coatings?
Ex.

A
  • Polymers are insoluble in water, however (polymer swells and forms a water-permeable membrane allowing for diffusion of drug)

Ex.
- Ethylcellulose (Aquacoat)
- Acrylic resins (methacrylates)

19
Q

What do you have to be aware of when using extended-release coatings?
How to avoid?

A

Dose dumping
Avoided if:
- film coating is mechanically sound
- enough coating is applied uniformly
- dosage form is not chewed or crushed prior to ingestion

20
Q

Disadvantages of using water as solvents in film coating

A
  • slow evaporation, longer drying time
  • appearance of picking or peeling or flakes
  • mottling (colour migration)
21
Q

Explain use of organic solvents for film coating

A

Faster drying
- expensive: efficient venting, plant optimization
- Safety issues: flammable, toxic

22
Q

What are plasticizers used for?
Examples?

A

Improves flexibility of the coatings, reduces risk of film cracking
Ex.
polyols: propylene glycol, glycerin, polyethylene glycols
Organic esters: diethyl phthalate, dibutyl sebacate, triethyl citrate, tributyl citrate, triacetin

23
Q

What type of colourants are preferred in film coatings? why?

A

Insoluble pigments
- reduce moisture which improves stability
- bulking agents: increase solid content without increasing viscosity
- less colour migration (mottling)
- Opacifying

24
Q

Purpose of anti-adherents in film coating? examples?

A
  • Reduces stickiness of film
  • prevents substrates agglomeration

Ex. Talc, magneisum stearates, glyceryl monostearate, high MW PEGs

25
Q

Purpose of surfactants in film coating? Examples?

A
  • Emulsifies water-insoluble plasticizers
  • improves tablet wettability
  • Ensure rapid dissolution of the coating in the stomach

Ex. Polysorbate 80, sorbitan monooleate, sodium dodecyl sulfate

26
Q

Explain the side-vented/perforated pan coater pan equipment for coating

A
  • most common
  • mixing and agitation of the tablet bed
  • sufficient heat input in the form of drying air
  • good exhaust facilities to remove dust and solvent air
27
Q

Explain spray coating. Airless vs. Air

A

Airless
- pumped under pressure through small nozzle to achieve atomization
- large scale operations

Air
- compressed air used to atomize coating liquid
- small scale operations

28
Q

What are fluidized bed coating used for in coating?
3 devices?

A
  • used for drying and granulating
  • taste masking, enteric & extended release coatings

3 devices
- Wurster process (bottom spray)
- granulation or conventional mode (top spray)
- Rotor process (tangential spray)

29
Q

What are some film coating problems

A
  • Picking (wet tablets stick and pull film of surface)
  • Orange peel (roughness)
  • Mottling (colour migration, lack of colour uniformity)
  • Twinning (tablets stick together)
  • Cracking and edge chipping
  • Wrinkling or blistering
30
Q

What are advantages and disadvantages of press coatings?

A

SOLVENT FREE coating
Adv
- incompatible materials can be made together
- no solvent needed

Disadv
- formulation and process of the coating layer requires some care
- Problems with lamination

31
Q

What are other examples of solvent-free coating?

A

hot-melt coating
electrostatic spray powder coating
dry powder coating
supercritical fluid- based coating
photocurable coating

32
Q

How long does disintegration QC test take for film coated vs. enteric coated (delayed release)

A

Film coated: 30 min
Enteric coated: 1 hr

PHARM 125 Midterm 1 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions