Formulations

Question 1

Different types of modified-release drug products

Answer 1

1) Extended-release (eg. controlled-released, sustained-release)
2) Delayed-release (released at time other than promptly after administration eg. enteric coated)
3) Target-release (releases drug at or near intended site of action eg. colon-targeting)

Question 2

What are the main formulation factors to be considered for Modified-release oral products?

Answer 2

Water permeation (controls rate at which drug dissolves). Dependent on:

• dissolution
• diffusion
• osmotic effects

Question 3

How does Dissolution affect modified release oral products?

Answer 3

Want decreased dissolution (solubility), resulting in the drug dissolving more slowly.
Can achieve this by:
1) use a less soluble form of the drug.
2) use excipient to decrease the dissolution rate (eg. form lipid barrier)
3) Microencapsulation (encapsulate microscopic drug particles with special coating material)
4) Pellet formation (coat drug powder onto bead, then beads coated with protective coating for sustained release)
5) Core tablets (core is slow drug release, outside shell contains rapid release dose)

Question 4

What factors can induce phase inversion?

Answer 4

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Question 5

What excipients are needed to create an emulsion?

Answer 5

• preservative (anti-microbial)
• oil
• emulsifier
• drug
• buffer (if for an IV emulsion)