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
Describe what the main parts of a capsule manufacturing machine?
- Gelatin storage tank
- Dip pan
- Drying kilns
- Automatic section
Empty gelatin capsules are to be kept at 13 to 16% moisture, if it’s too moisturised or too dry, what happens to the capsules?
- Too moist, capsule becomes too soft
2. Too dry, capsule becomes too brittle and starts cracking
Describe the mechanism of filling capsules?
- Two halves of the capsule are separated
- Exact dose is placed in the smaller half (body)
- Cap is then locked onto smaller half
- Filled capsule is removed from machine
Describe the automatic tableting filling process?
- Ingredients are all mixed together
- Placed into a milling and sieving machine (tableting function)
- Capsule filters and then gets packaged
What are the excipients that are in powder filled capsules? (similar to tableting)?
- Diluents: plug forming properties
- Lubricants: reduce powder to metal adhesion
- Gildants: Improve powder flow
- Disintergrants: produce disruption of the powder mass
- Wetting agents: improve water distribution
- Stabilisers: Improve product stability
What are the formulation advantages of capsules?
- Requires fewer excipients
- Commonly used for clinical trials
- Has more versatility: filled with powders, granules, pellets, tablets and liquids
- Good for controlled release - Reduces stability problems with sensitive drugs and product combinations
- More efficient pharmaceutical development means faster speed to market
