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14 Cards in this Set
- Front
- Back
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Which for of tablet coating is most commonly used? 1. Sugar coating 2. Film coating 3. Compression coating |
2. Film coating |
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What are the advantages of using a film coat rather than uncoated? |
1. Improves mechanical properties 2. Improves appearance 3. Can control the rate and duration of drug release 4. Can target where the drug is released in the GI |
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What are the ingredients required for film coating tablets? |
1. Film forming polymers 2. Solvent (organic or aqueous) 3. Plasticiser (glycerol, only sometimes used) 4. Colorants (optional) 5. Flavour (optional) |
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What is the type of film coating used for immediate release/ regular release drugs? |
These are coated by polymers that are soluble in the stomach. |
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What is the type of film coating used for enteric coated drugs? |
These are coated by polymers that are insoluble in the stomach, but soluble at ph>4 (in the intestines). This prevents drug degredation and stomach mucosal irritation. |
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What is the type of film coating used for controlled release drugs? |
These are insoluble film polymers used. They are not soluble anywhere in the GI, but they are permeable so that drug can diffuse through the insoluble coat. |
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What is the difference between coating solutions and coating emulsions? |
Coating solutions has coating solvent and excipients (colorants, plasticisers, etc).
Coating emultions has polymers dissolved in volatile organic phase plus other excipients. This is emulsified with another aqueous phase. |
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What are common problems associated with film coatings? |
1. Poor adhesion to tablet 2. Tablet abrasions 3. Filling tablet markings 4. Rough surface and cracks 5. Variations in colour 6. Picking and sticking (overcoating, so tablets stick together) |
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What are the 4 steps to producing film coated tablets? |
1. Tablets are agitated in a coating apparatus 2. Coating solution sprayed onto tablet surface 3. Warm air passed over tablets to help dry 4. When solvent is gone, tablets are coated with the solid component of the original coating formulation |
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What are the qualities of sugar coated tablets? |
1. Older method, not as common. (replaced by film) 2. Increased palatability 3. Mainly uses sucrose 4. Coating is water soluble and dissolves quickly after swallowing. |
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What are the steps involved with sugar coating? |
1. Sealing - protects tablet from water with resin 2. Subcoating - sugar solution, then powder coating and drying 3. Smoothing - application of simple syrup + opacifier (titanium dioxide) 4. Color coating 5. Polishing (mixture of waxes in polishing pan) 6. Printing |
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What are common issues with sugar coatings? |
1. Take 8+ hours 2. Rough irregular surfaces 3. Difficult to get uniform coat 4. Tablet weight increased, shipping cost increases 5. Larger tablets might be hard to swallow |
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What is compression coating? |
Coating materials, in the form of granules and poweder, is compressed onto tablet with a special press. More uniform than sugar coating. Less material so tablets are lighter and smaller. This is an anhydrous process to safe for water sensitive drugs. |
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What are reasons for coating tablets? |
1. Protect drug from light, degredating, moisture, low pH 2. Taste masking 3. Modify drug release 4. Reduce GI irritation 5. Marketing |
