Advanced Coatings [Dr Green] Flashcards Preview

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Flashcards in Advanced Coatings [Dr Green] Deck (18):
1

List 5 reasons why tablets are coated

Aesthetics
Mask taste
Modify drug release
Protection
Improve mechanical properties

2

List 3 types of coating

Sugar coating
Enteric coatings
Film coatings

3

List 4 ways that a coating can be applied to tablets

Sprayed
Compressed
Mixed
Submerged

4

Outline the tablet manufacturing process

API and excipients
Mixing and granulation
Drying
Compression
Coating
Packaging

5

What are the benefits of using a sugar coating?

Used to mask the flavour of unpleasant tasting drugs
Protects the API from light and moisture - improves drug stability

6

List the 5 excipients of a sugar coating

Adds sweetness:
Sucrose
Glycerol
Improves mechanical strength:
Croscarmellose sodium
Gelatin
Gum arabic

7

List the 6 excipients of a film coating

Polymers e.g. methylcellulose
Solvent e.g. water, alcohol
Plasticiser
Colourants
Flavours
Anti-tack agents

8

What is the purpose of the plasticiser in a film coating?

Adds mechanical flexibility
Lowers glass transition temperature:
Embed between polymer chains spacing them apart
Increases free volume, elasticity and softness of film

9

List 3 sub-types of modified release

Delayed = not released until after stomach - protect stomach, drug or improve absorption
Repeat action = multiple doses in a single dosage unit, 2 layer tablets
Sustained = quick initial burst followed by long slow release

10

List 4 benefits of modified release where it is necessary

Less fluctuation in drug blood levels
Frequency reduction in dosing
Enhanced convenience and compliance
Reduction in adverse side effects

11

List 3 criteria that drug candidates must adhere to for modified release

Must:
Be uniformly absorbed
Possess good margin safety
Be administered in small doses

12

What is the purpose of an enteric coating?

Prevents the tablet's disintegration or dissolution in the stomach but allows it in the small intestine
- Improves bioavailability

13

What occurs in the Duodenum?

Site of most chemical digestion
Chemical secretions from liver, gall bladder and pancreas mix here
Absorption of vitamins, minerals and other nutrients
Short residency time

14

What occurs in the Jejenum?

Mucosal surface covered in villi
Main section for nutrient absorption
Good vascular supply
Slight increase in pH compared to duodenum

15

What occurs in the Ileum?

Smaller in diameter and thinner walls
Contains peyers patches which contain a large number of lymphocytes
Main function is to absorb vitamin B12 and bile salts

16

Why were enteric coatings developed?

Considerable variation in patient gastric residence time

17

What is eudragits?

A family of polymers of varying properties

18

Describe the disintegration test for enterically coated tablets

Introduce 1 tablet into each tube
Place in 0.1M HCl, leave for 2 hours (stomach)
Check for signs of cracking (bad)
Place in phosphate buffer pH6.8 and leave for 1 hour (small intestine)