Advanced Coatings [Dr Green] Flashcards
List 5 reasons why tablets are coated
Aesthetics Mask taste Modify drug release Protection Improve mechanical properties
List 3 types of coating
Sugar coating
Enteric coatings
Film coatings
List 4 ways that a coating can be applied to tablets
Sprayed
Compressed
Mixed
Submerged
Outline the tablet manufacturing process
API and excipients Mixing and granulation Drying Compression Coating Packaging
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
List the 5 excipients of a sugar coating
Adds sweetness: Sucrose Glycerol Improves mechanical strength: Croscarmellose sodium Gelatin Gum arabic
List the 6 excipients of a film coating
Polymers e.g. methylcellulose Solvent e.g. water, alcohol Plasticiser Colourants Flavours Anti-tack agents
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
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
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
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
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
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
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
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
