Polymers 6: Hard Capsules Flashcards
Define what capsules are?
- Solid preparations with hard or soft shells of various shapes and capacities that usually contain a single dose of active substance.
- Intended for oral administration
What are the two different capsule classifications?
- Hard capsule: Two piece
2. Soft capsules: One piece
What are the raw materials that are used in the manufacture of capsules?
- Gelatin (or alternative polymers)
- Water
- Colourants
- Optional materials (aid and preservatives)
- Plasticers (soft capsules)
Describe the process of acid production of gelatins?
- Using collagen (animal waste product)
- Acidification to pH 4 to reduce pH
- Heating from 50 degrees to boiling
- Elimination of fat (due to gelatine being protein in nature)
- Filtration
- Vacum evaporation (evaporate solvent)
- Drying (to form powder)
Describe the process of alkali production of gelatins?
- Treatment with NaOH
- Removing NaOH
- Treatment with acid to adjust pH
- Heating from 50 degrees to boiling
- Demineralisation: calcium phosphate
- Filteration
- Vacum evaporation
- Drying (to form powder)
What is gelatin a derivative for?
Form of collagen
What are the properties of gelatin?
- Non toxic
- Soluble at body temperature
- Good film forming properties
- Solutions of high concentration 40% w/v are mobile at 50 degrees
- Changes from gel to solution at temperatures above room temperature
Describe what bloom strength is and how it’s measured?
- Measure of gel rigidity
- Plunger is used to push the solution into gel by 4mm
- For hard capsules it’ll form a 200 to 250g
- For soft capsules it’ll form 150g added with plastiscer to make it softer
What is the gelling point?
The point at which the gel turns into solution
What are some of the problems that occur with gelatin and the replacement options available?
- It’s an unacceptable product for vegetarians and for religious regions
- HPMC: Hydroxypropylmethylcellulose (used as replacement)
Describe the composition of hard capsules?
- Two piece shell (body and cap) which lock together
- Must be accurately filled
- Not react with gelatin
- And leak out of shell
What are the type of dry solid materials for filling up hard capsules?
- Powders
- Pellets
- Granules
- Tablets
What are the type of semi solids and liquid materials for filling up hard capsules?
- Semi solids
- Thermo-softening mixtures
- Thixotropic mixtures (ability for material to return to original shape)
- Pastes - Liquids
- Non aqueous liquids (has to be from oil)
What is the purpose of having a capsule in a capsule?
Important in clinical trials to prove unbiased results
What is the sequence of two piece hard gelatin manufacture?
- The capsule is dipped into HPMC and cold
- The spinning motion cools down the liquid
- Drying process (50 degrees)
- Stripping
- Cutting
- Joining