Polymers: Hard Capsules Flashcards
Define: Capsule
Solid preparations with hard or soft shells of various shapes and capacities
Usually contain a single dose of active substance
Intended for oral administration
Name the 2 types of capsule
Hard capsule (2 piece) Soft capsule (1 piece)
List 5 raw materials used in the manufacture of capsules
- Gelatin (or alternative polymers)
- Water
- Colourants
- Optional material (process aids and preservatives)
- Plasticisers (in soft capsules)
How is gelatin produced?
From collagen
Either via an acid (gelatin A) or alkali (gelatin B) process
Explain the acid process of gelatin production
- Acidification to pH 4
- Heating from 50C to boiling
- Elimination of fat
- Filtration
- Vacuum evaporation
- Drying
= GELATIN A
Explain the alkali process of gelatin production
- Treatment with and removal of NaOH
- Treatment with acid to adjust pH
- Heating from 50C to boiling
- Demineralisation
- Filtration
- Vacuum evaporation
- Drying
= GELATIN B
List 5 properties of gelatin
- Non-toxic
- Soluble at body temperature
- Has good film-forming properties
- Solutions of high concentration (40% w/v) are mobile at 50C
- Changes from gel to solution at temperatures just above room temperature
List 3 criteria of the filling material of a hard capsule
- Be accurately filled
- Must not react with gelatin
- Must not leak out of the shell
What does a hard capsule shell consist of?
2 pieces - a body and cap - which lock together
List 3 types of material that are used to fill hard capsules
- Dry solids = powders, pellets, granules, tablets
- Semi-solids = thermosoftening mixtures, thixotropic mixtures, pastes
- Liquids = non-aqueous liquids
How are hard capsules filled?
- The 2 halves are separated
- An exact dose is placed in the smaller half (the body)
- The cap is then locked onto the smaller half
- The filled capsule is removed from the machine
List 6 excipients used in powder filled capsules
- Diluents = give plug-forming properties
- Lubricants = reduce powder to metal adhesion
- Glidants = improve powder flow
- Wetting agents = improve water penetration
- Disintegrants = produce disruption of the powder mass
- Stabilisers = improve product stability
List 3 advantages of formulating capsules
- Typically require fewer excipients
- Versatile - can be filled with a variety of substances
- Reduced stability problems with sensitive drugs and combination products
