Surfactants

Question 1

Discuss Surfactants

Answer 1

• Combines in one molecules
  
  • Hydrophobic and hydrophilic systems
• 4 Classes: Anionic, Cationic, Non-ionic, Zwitterionic
• Strongly absorb at interfaces
• Relatively low concentrations reduce tension
• Form a film at an interface - controls interfacial properties
• Reduce work needed to expand interfacial contact
• Enhance solubility via formation of micelles and other colloidal particles

Question 2

Discuss Micelles

What is the Critical Micelle Formation (CMC)

Answer 2

• Association between surfactant monomers
  
  • 10 to 100 molecules for ionic surfactants and up to 1000 for non-ionic surfactants
• Critical Micelle Formation
  
  • Surfactant concentration at which micelles first start to form

Question 3

How are liposomes formed?

Answer 3

• Phospholipids come together to form liposomes

Question 4

Discuss the Impact of Solutes on Surface Tension

Answer 4

• Linear decrease in y with logarithm of concentration

Question 5

How may drugs be surface-active?

Answer 5

• Relatively high concentrations generally needed to reduce tension
• Absorb onto cellular interfaces
• Absorb onto the surface of proteins
• Absorb to surfaces of containers

Question 6

Discuss the Solubilisation with Surfactants

Answer 6

• Surfactants may absorb onto hydrophobic drugs, increasing solubility
• Hydrophobic drugs may solubilised in micelle cores