Liposomes in drug delivery.

NDDS

1. Liposomes In Drug Delivery
Presented by:
Chinchole Pravin Sonu
)M.PHARM 2
nd
SEM(
DEPARTMENT OF PHARMACEUTICS & QUALITY ASSURANCE
R. C. Patel Institute of Pharmaceutical Education and Research,
shirpur.

2. Overview
•Definition of liposomes
•Classification of liposomes
•Structure of liposomes
•Preparation of liposomes
•Purification of liposomes
•Characterization of liposomes
•Liposome-cell interaction
•Liposomes as drug delivery systems
•Targeted Drug Delivery

3. Definition
•Liposomes are spherical microscopic vesicles
consisting phospholipids bilayers which
enclose aqueous compartments

4. Classification
•Small unilamellar vesicles
(SUV), 25 to 100 nm in size
that consist of a single
bilayer
•Large unilamellar vesicle
(LUV), 100 to 500 nm in
size that consist of a single
bilayer
•Multilamellar vesicle
(MLV), 200 nm to several
microns,that consist of two
or more concentric bilayer

5. –Described by Bangham in 1965
–Study of membranes

6. Structure of Liposomes: Phospholipids
Three carbon glycerol
Polar Head Groups

7. Structure of Liposomes: Phospholipids

8. Phase Transition Temperature Tm

9. Phase Transition Temperature Tm

10. Membrane permeability

11. Cholesterol
•Because of its rigid steroid ring system which interferes with
motion of fatty acid tails, stabilizes the lipid bilayer and
decrease the leakage of encapsulated drug

12. DSC of Chol/DSPC
10 20 30 40 50 60 70 80
0
2
4
6
8
10
12
DSPC
5% Chol
10% Chol
20% Chol
30% Chol
35% Chol
40% Chol
50% Chol
60% Chol
SChcPC
E
n
d
o
D
C
p
(
K
c
a
l
/K
/
m
o
l)
Temperature (ºC)

MHC of SChcPC and DSPC

13. Non Structural Components

14. Preparation of liposomes: Mechanical
Dispersion

15. Processing of lipids hydrated (MLVs)
by physical means
•Micro-emulsification of liposomes

16. Processing of lipids hydrated (MLVs) by physical means
EmulsiFlex High Pressure Homogenizar

17. Processing of lipids hydrated (MLVs) by physical means:
EmulsiFlex High Pressure Homogenizar

18. Purification of Liposomes

19. Purification of Liposomes
•Gel Filtration Column Chromatography

20. Purification of Liposomes
•Dialysis

21. Purification of Liposomes
•Centrifugation

22. Stability of Liposomes
•Chemical degradation
•Physical degradation
•Prevention of chemical
degradation
•Prevention of physical
degradation

23. Preparation of Sterile Liposomes

24. Liposome Characterization
•Determination of Drug Content
•Determination of Percent Capture
•Lamellarity
•Phosphate assay
•Cholesterol assay

25. Liposome characterization
•Size distribution
•Zeta potential
•Tm by DSC
•Stability: Drug, lipid and liposome

26. Liposome-cell interaction

27. Liposomes in drug delivery
•Protect the encapsulated drug from metabolic
degradation
•Increase the half-life of drug
•Reduce the systemic toxicity of drugs
•Could be used as sustained release vehicles
•It is possible to target them to selected tissues
or cell
•Biodegradable and biocompatible

28. Types of liposomes

29. Stealth or PEG-Liposomes