What are tablets?
solid preparations containing a single dose of more than one drug
What are the different types of tablet?
caplet, effervescent, dispersible, buccal, sublingual, chewable, vaginal/rectal tablets, MR, coated, lozenges
Why would you coat a tablet?
- to protect the drug
- to mask the taste
- for identification
- easier to swallow
- to change the release properties
What are the different types of coating?
film (polymers) or sugar coated (SC)
What are capsules?
One or more drugs enclosed in a gelatine shell
What is the difference between hard a soft gelatine?
Hard gelatine has a 2 piece outer shell and can be filled with powder, granules or pellets whereas soft gelatine has a one piece gelatine shell and it can be opened for external use
What is the difference between powders and granules?
powders are finely divided solids whereas granules are powders that have been aggregated together to form larger particles. Granules are for internal use only.
What are the excipients needed in oral solid forms?
- dilutents/fillers to add bulk (lactose, cellulose)
- binders to make the granules (gelatine, cellulose)
- disintegrants to break the tablet up (starch)
- lubricants to improve flow properties (magnesium stearate)
- colourants (E-number)
How do effervescent tablets work and what are the excipients needed for this?
A reaction occurs between a carbonate and weak acid to produce CO2 which breaks the tablet up
-an example of a carbonate and weak acid is sodium carbonate and citric acid
What specific excipients are needed in chewable tablets?
sweeteners (to aid solubility and for taste e.g. mannitol) and flavourings
What are the 3 different types of modified release forms?
- delayed release
- enteric coating (pH dependent)
- extended release
How does enteric coating work?
It prevents release of drug in the stomach to either protect the drug or protect the stomach
What are the different methods used for MR?
- Matrix system: made of polymers and can be split
- Reservoir/membrane system: this coating creates a semi-permeable barrier, it’s made from polymers and plasticisers and can NOT be split
What is a desiccant and what can it help maintain?
A desiccant is a drying substance and is used for stability
What are the advantages of tablets and capsules?
- very stable
- convenient
- easy to make and at a low cost
- taste can be masked
- release can be modified
What are the disadvantages of tablets and capsules?
- slow onset of action
- 1st pass metabolism
- systemic action and side effects
- gelatin issues
- difficulty swallowing
What are the advantages of powders and granules?
- very stable and can be reconstituted to liquids
- accurate dosing from sachets
- faster onset of action
- good for large doses
What are the disadvantages of powders and granules?
- 1st pass metabolism
- systemic action and side effects
- difficult to mask taste
