Coatings Flashcards
1
Q
Reasons for coating medication
A
- Protect API from environment (light, moisture)
- Masking the taste
- Improve the ease of swallowing large dosage forms
- Masking any batch differences in the appearance
- Imparting modified-release characteristics
2
Q
Three types of coating processes
A
- Film coating – deposition of a thin film of a polymer-based formulation onto the surface of a tablet, capsule or multiparticulate core
- Sugar coating – application of sucrose-based coating formulations, usually to coat tablet cores
- Compression coating – the compaction of granular material around a preformed tablet core
3
Q
Two types of film coating
A
- Immediate-release film coatings: ‘Non-functional’ coatings that are readily soluble in water and applied to achieve certain property
- Modified-release film coatings: gastro-resistant coatings
4
Q
Film-coating process
A
- Application of liquid polymer-based formulations to the surface of the solid dosage form
- The coating liquid is sprayed onto a rotating dosage form
- The drying conditions employed in the process result in the removal of the solvent, so thin film forms
5
Q
What materials are used for film coating formulations
A
- Polymer
- Plasticiser
- Colourants
- Solvent/vehicle
6
Q
Name some requirements for film-coating polymers
A
7
Q
Why are plasticisers so commonly used as coatings
A
- Plasticisers are added to increase film flexibility and to reduce residual stresses within the coating during its drying
8
Q
What is Tg value
A
- Glass transition temperature
9
Q
Why do we sugar coat medication
A
- Application of sucrose-based coating formulations to tablet cores
- All ingredients are readily soluble or disintegrate rapidly in water
- Immediate-release applications
- All sugar-coated tablets should have a smooth, rounded contour, with even colour and a glossy finish
- They are easy to swallow and sugar masks the taste
10
Q
Differences between sugar coating and film coating
A
