Formulation of Advanced or Complex Medicines 17 Flashcards
Give examples of lubricants used in tablets and capsules?
Magnesium stearate
- most used excipient in solid oral dosage forms
- 95% of licenced medications but quite hydrophobic
- sweet spot - don’t waterproof particles as tablet will pass through the GI tract without being absorbed
Sodium stearyl fumarate
Stearic acid
Polyethylene glycol
How does a boundary lubricant work?
Forms film at surface of die wall and tablet
- e.g. magnesium stearate
How does stearic acid work as a lubricant?
Melts to form a boundary layer
What is an anti-adherent?
Problem with sticking on faces of tablet punches
- particularly with embossed punches
- fault called ‘picking’
Magnesium stearate has a secondary role in preventing sticking
Talc and starches are also used
How can the flow of active pharmaceutical ingredient and excipients be improved?
Use glidants in the formulation
What is a glidant used in tablets and capsules?
Powders that coat other particles and reduce interparticulate forces improving flow of the mass
Give examples of glidants used in tablets and capsules?
Colloidal silicon dioxide
- use levels < 0.5%
Talc
- use levels > 1.0%
How do glidants and lubricants work?
Both act on the surface of particles
If not properly dispersed, do not function
A minimum optimum concentration gives maximum effect
- if exceeded adverse effects occur
Concentration to use related to size of surface to be covered
- product of both size and shape of particles
How can the distintegration or deaggregation of a tablet or capsule be improved?
Use a wetting agent in your formulation
What is the function of a wetting agent?
To improve wetting of hydrophobic actives
Give examples of wetting agents used in tablets and capsules
Sodium lauryl sulphate
Polysorbate 80
Why are wetting agents important in tablets and capsules?
Need water next to active to absorb into GI tract
What can be used to improve the stability of tablets and capsules under normal storage conditions?
Stabilisers
What can be used to improve patient compliance due to a bitter active pharmaceutical ingredients?
Flavourings
What can be used to improve an uneven colouring, or to distinguish tablets and capsules from others?
Colourants
