liposomes in drug delivery
TRANSCRIPT
Liposomes In Drug DeliveryPresented by :
Chinchole Pravin Sonu(M.PHARM 2nd SEM)
DEPARTMENT OF PHARMACEUTICS & QUALITY ASSURANCE
R. C. Patel Institute of Pharmaceutical Education and Research, shirpur .
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
Definition
•Liposomes are spherical microscopic vesicles consisting phospholipids bilayers which
enclose aqueous compartments
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
–Described by Bangham in 1965–Study of membranes
Structure of Liposomes: Phospholipids
Three carbon glycerol
Polar Head Groups
Structure of Liposomes: Phospholipids
Phase Transition Temperature Tm
Phase Transition Temperature Tm
Membrane permeability
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
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
Endo
Cp
(Kca
l/K/m
ol)
Temperature (ºC)
MHC of SChcPC and DSPC
Non Structural Components
Preparation of liposomes: Mechanical Dispersion
Processing of lipids hydrated (MLVs) by physical means
•Micro-emulsification of liposomes
Processing of lipids hydrated (MLVs) by physical means
EmulsiFlex High Pressure Homogenizar
Processing of lipids hydrated (MLVs) by physical means: EmulsiFlex High Pressure Homogenizar
Purification of Liposomes
Purification of Liposomes
•Gel Filtration Column Chromatography
Purification of Liposomes
•Dialysis
Purification of Liposomes
•Centrifugation
Stability of Liposomes
•Chemical degradation•Physical degradation•Prevention of chemical
degradation•Prevention of physical
degradation
Preparation of Sterile Liposomes
Liposome Characterization
•Determination of Drug Content•Determination of Percent Capture•Lamellarity•Phosphate assay•Cholesterol assay
Liposome characterization•Size distribution•Zeta potential•Tm by DSC•Stability: Drug, lipid and liposome
Liposome-cell interaction
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
Types of liposomes
Stealth or PEG-Liposomes