Liposomes

1. By
SHIVA
[email protected]
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2. Liposome are membranous vesicles formed by
dispersion of phospholipids in aqueous media.
They are small hollow spheres bound by a double
layer of lipid molecules in which the hydrophilic
heads of the molecules form the inner and outer
surface of the sphere, while the lipophillic tails
interwine in the middle.
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3. 3
HYDROPHOBIC
HYDROPHILIC

4. ADVANTAGES:
•Flexibility in the structure in entrapment of water
soluble as well as insoluble drugs.
•Biodegradability
•Efficient control of release.
•Resemblance to natural membrane structures.
•Increased targeting prospects.
•Beneficial modification of pharmacokinetics of the
drug.
•Facilitation of transport across membranes.
•Adjuanticity of vaccines
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5. DISADVANTAGES:
The development of liposomes at industrial level is
difficult due to its physiological and
physicochemical instability.
They aggregate and fuse together upon prolonged
storage disturbing the reproducibility.
They are prone to degradation by oxidation and
hydrolysis.
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6. Size and size distribution
Lamellarity
Entrapped volume
Solute distribution
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7. Classification
based on structural parameters
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Based on structural 
MLV
Multilamellar
Large
vesicles
(>0.5 um)
OLV
oligolamellar
vesicles
(>0.1-1.0
um)
UV Unilamell
arVesicles (all
 size ranges)
MVV
Multivesicula
rvesicles
(> 1.0 UM)
MUV
GUV
>1um
SUV
20-
100nm
LUV
>100nm

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Multilamellar vesicles

Unilamellar vesicles

9. Endocytosis
Adsorption to cell surface
Fusion with plasma cell membrane
Transfer of liposomal content
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10. Physical dispersion methods
Solvent dispersion
Detergent solubilisation
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11. Hand shaking method
Non shaking method
Pro liposomes
Freeze drying method
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12. 
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13. •SOLVENT DISPERSION METHODS:
1.Ethanol injection
2.Ether injection
3.Water in organic phase
4.Double emulsion vesicles
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14. Ethanol/Ether injection method
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15. •Handling of liposomes:
Liposomes have a standard composition- egg,
lecithin, cholesterol, phosphotidyl glycerol in molar
ratio of 0.9:1:0.1. these lipids are stored as solids
or in organic solution at -20°C or -70°C in order to
reduce oxidation. The solvent is mixture of
chloroform and methanol(2:1). Stored in dark
glass vessels.
•Drying : Gentle warming at 20°C to 40°C under
reduced pressure. Rapid rotation increase surface
area for evaporation.
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16. •Commonly purified by gel filtration column
chromatography or dialysis or centrifugation.
•In column chromatographic separation, Sephadex
G-50 is most widely used material.
•In dialysis method, hollow fiber dialysis cartridge
may be used.
•The separation of liposomes by centrifugation
method depends on the size as well as the
composition of the bilayers.
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17. •IV route is the most popular route. Three
pathways are there for drug release.
I.Destabilization of liposomes
II.Delivery of liposomes to the monounuclear
phagocyte system(MPS)
III.Sustained release of liposome encapsulated drug
by long circulating liposomes.
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18. Enzyme replacement therapy
Delivery of antibodies, antigens and vaccines
Hormones and blood factors
Blood substitutes
Interferon
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