Lecture 3

Question 1

Factors that affect particle recognition & phagocytosis?

Answer 1

• size
• charge
• surface hydrophilicity

Question 2

Liposomes drug incorporation ?

Answer 2

1) encapsualted in aqueous phase
2) taken in phospholipid part of bilayer: hydrophobic drugs
3) Can be adsorbed: Hydrophobic & hydrophillic drugs

Question 3

Liposomes can be classified on the basis of composition and in vivo application:

Answer 3

A.conventional liposomes:neutral / -ve charged (Used for passive targeting Cells of MPS)
B.sterically stabilized ( stealth ) liposomes:With hydrophilic coat (PEG) to make drug stay in circulation for long time
C. Immuno Liposomes: active targeting purpose.
D.Cationic Liposomes: Positively charged and responsible for targeting of genetic material ( 3rd order targeting)

Question 4

Mechanisms of maturation or Modes of liposomes/cell interaction?

Answer 4

1- Fusion of liposomes with the cells membrane → lipid portion becomes a part from the cell membrane.
2- Adsorption on the cell membrane.
3- Endocytosis of the vesicles by the cell.
4-Lipid transfer: Exchange of bilayer components , eg. cholesterol, lipids & membrane bound molecules with components of cell membrane.