Film coating

Question 1

What are the different types of coating processes?

Answer 1

• Film coating
• Sugar coating
• Compression coating
• Gelatin coating
• Electrostatic coating

Question 2

What is film coating?

Answer 2

-The application of a thin layer of material to the surafce of the tablet, capsule or pellet

Question 3

Why film coat?

Answer 3

• Modification of dosage form apperanace
• Blinding for clinical trials
• Product identification
• Phsycological reasons
• Taste masking
• Stability
• Modifying drug release

Question 4

What are the two different types of coating?

Answer 4

• Immediate release

- Modified release (can be pH dependent or pH independent

Question 5

What are the ideal properties of film coat?

Answer 5

• Non-toxic
• Soluble in appropriate solvents
• Good film former - at appropriate temp
• Good mechanical strength
• Smooth Stable
• Coherent continous coating with no holes

Question 6

What are the common film coating ingredients?

Answer 6

• Polymers
• Plasticisers
• Colourants/pigments
• Solvent vehicle (organic vs aqueous solvents )
• Pore-formers
• Anti-tack agents

Question 7

Give examples of polymers used for immediate release of film coating?

Answer 7

• Cellulose derivatives e.g hydroxypropyl methylcellulose
• Vinyl derivatives (PVP)
• METHACRYLIC ACID COPOLYMERS
• Phthalate esters

Question 8

Hydroxypropyl methylcellulose are widely used, readily solubl ein aqeous media

• Good film former
• Good mechanical properties
• Easy to apply. TRUE OR FALSE?

Answer 8

TRUE

Question 9

PVP has limited use in film coating because of its inherent tackiness. TRUE OR FALSE?

Answer 9

TRUE

Question 10

Water is sually the prefered solvent. TRUE OR FASLE?

Answer 10

TRUE

Question 11

What are the ads and disads for organic solvents?

Answer 11

Disads 
-Environmental issues 
-Safety
-Cost 
-solvent residues 
Ads 
-Sometimes preferred for moified release as they can provide a more flexible coating 
-More rapid application

Question 12

What are plasticisers?

Answer 12

-They are usually small molecules that physically impose themselves between polymer strands

Question 13

Plasticeers lowers the glass transition temperature of the polymer and decreases brittleness. TRUE OR FALSE?

Answer 13

TRUE

Question 14

pIGMENTS PROVIDE AN ELEGANT COSMETIC APPEARANCE. true or false?

Answer 14

true

Question 15

What are pigments consisted of?

Answer 15

• Iron oxide

- Titanium dioxide

Question 16

What is a lake pigment?

Answer 16

-A pigment manufactured by precipitating a dye with an inert binder

Question 17

Pigments are usually water insoluble and opage and can add light protective properties to the dosage form. TRUE OR FALSE?

Answer 17

TRUE

Question 18

Pore formers are only used for water insoluble coatings. TRUE OR FALSE?

Answer 18

TRUE

Question 19

Starch cannot be used as a pore formers, TRUE OR FALSE?

Answer 19

FALSE

Question 20

Simply decsribe the process of film coating?

Answer 20

• Film coating ia the deposition of thin uniform film of plymer formulations surrounding a tablet/capsule/pellet
• Polymers are dissolved in organic/aqeous solution or suspended as an aqueous suspension
• Polymer solutions/suspensions are sprayed through a nozzle uner air pressure which atomises the liquid breaking it up itno tiny droplets
• Meanhwile, tablet cores are tumbling/fluidised in the coater and are exposed to an air inlet of high temp
• Polymer droplets hit the tablets or pellet core, and the solvent/water evaporates
• Dried material then remain on the surface of the tablets/pellets
• Droplets build up until a coherent coat has been formed

Question 21

Describe the process of film formation from polymer solution?

Answer 21

• Polymer soltuions consits of molecular chains polymers dissolved in a soltion
• Film coating involves the concentration of the polymeric chains by evaporation
• The polymer chains start to coalesce
• Further gradual coalescence and polymer interdiffusion take place
• Autohesion is the lat stage of the process

Question 22

Describe the process of film formation from suspensions?

Answer 22

• Polymers exists as discrete particles in suspension
• Evaporation causes the polymeric particles to come into closer proximity to each other
• The chains start to deform
• The particles start to coalesce, often due to capillary action
• Further gradual coalescence and polymer interdifusion take place
• Particles contours vanish as they cease to be discrete particles, macromolecules of adjacent particles mix through interparticular diffusion

Question 23

What is the diffusion of the polymeric chains between particles?

Answer 23

-This is a process of vsicous flow, a prerequisite of which is the existence of free volume into whcih the polymer chains can flow and intermingle

Question 24

What factors influence film coating?

Answer 24

• Temperature
• Molecular weight of the polymer
• Packing and orientation of the polymer
• Side groups/side chains
• Flexibility of the polymer chain
• Presence of other materials

Question 25

List the types of spray coating equipment?

Answer 25

- Pan coater (primary process for tablets) | - Fluid bed coater (primary process for pellets/granules

Question 26

What are the critical parameters for pan coating?

Answer 26

- Pan speed - Spray orientation - Inlet and outlet air temperature - Pump speed/spray rate - Atomising air pressure - Exhaust facilitites to remove dust

Question 27

What are fluid bed caoting critical parameters?

Answer 27

- Fluidisation rate - Spray orientation - Inlet and outlet air temperature - Pump speed/spray rate - Atomising air pressure

Question 28

What is involved in wurster coating?

Answer 28

-The concept is to seperate particles from each other in a heated air stream and spray a coating onto the particles whilst they are suspended

Question 29

What si the inner area of wurster coating?

Answer 29

-Is a high velocity zone which seperates the particles and transports them past the spray nozzle, after passing the nozzle the poarticles enter the expanded area, slow down and fall back to the outer section of the fluid bed product bowl

Question 30

What are the problems with film coating?

Answer 30

- Sticking - Lack of coherent coating - Poor elegance - Bridging - Film cracking - Peeling

Question 31

What is sugar coating?

Answer 31

-A succesive application of sucrose to the tablet cores

Question 32

Why is sugar coating used?

Answer 32

- Sealing of tablet cores - Subcoating - Smoothing - Colouring - Polishing - Printing

Question 33

Sugar coating produces a much thicker coating than film coating and also results in shinny surface and tatse can be easily manipulated. TRUE OR FALSE?

Answer 33

TRUE

Question 34

What is compression coating?

Answer 34

- Compressing a granular material around a tablet core, requires a special tablet press and is technically challenging

Question 35

What are the technical challenges of compression coating?

Answer 35

- Allignment of coating metrials and route | - Sensitive to irregularities in granule size

Question 36

What is gelatin coating?

Answer 36

-Compressed tablet coated with gelatin to make capsules easier to swallow

Question 37

Gelatin can be spray coated. TRUE OR FALSE?

Answer 37

TRUE

Question 38

An alternative to spray coating gelatin onto capsules is cold shrinking of flexible gel capsules. TRUE OR FALSE?

Answer 38

TRUE

Question 39

What is electostatic coating used to create?

Answer 39

-It is based on photocopying technology used to create tablet coatings with highly distinctive patterns important to brand identification

Question 40

Electrostaic coating can also be used to load a very low dose of drugs onto tablets. TRUE OR FALSE?

Answer 40

TRUE