Transcript Document
SEMINAR ON
SEMINAR ON ……..
LIPOSOMES
AND
NANOTECHNOLOGY
PRESENTED BY:
MAHESH DABHI
Department Of Pharmaceutics and Pharmaceutical Technology,
L.M. College of Pharmacy.
List of contents
o Introduction:
o Advantages with use of liposomes as drug delivery system.
o Classification
o Manufacturing of liposomes
o Liposome characterization and control
o Stability consideration for liposomal formulations
o Regulatory science of liposome drug products
o Drug release from liposomes
o Applications
o Recent innovations
o Approved liposome products
o References
INTRODUCTION
o The preparation of liposomes, with
entrapped solutes, was demonstrated for
the first time in 1965 by Prof. A.D.
Bangham of the United Kingdom.
Definition
o “Liposomes are microscopic spheres made from fatty
materials, predominantly phospholipids.
o “made up of one or more concentric lipid bilayers,
and range in size from 50 nanometers to several
micrometers in diameter”
Advantages with liposomes
o Suitable for delivery of hydrophobic, hydrophilic and
amphipatic drugs and agents
o Chemically and physically well characterized entities
o Biocompatible
o Suitable for controlled release
o Suitable to give localized action in particular tissues.
o Suitable to administer via various routes
Classification
o Classification based on size of
liposomes
o Classification based on method of
preparation
o Classification based on composition
and in vivo application
Classification based on size
Small unilamellar vesicles
Medium sized unilamellar vesicles
Large unilamellar vesicles
Giant unilamellar vesicles
Unilamellar vesicles
Oligolamellar vesicles
Multilamellar large vesicles
Multivesicular vesicles
Classification based on method
of preparation
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Vesicles prepared by extrusion method.
Vesicles prepared by French press.
Vesicles prepared by fusion.
Vesicles prepared by reverse phase
evaporation.
o Frozen and thawed MLV.
o Dehydration and rehydration vesicles.
o Stable plurilamellar vesicles.
Classification based on
specific properties
o Conventional Liposomes
Long circulating liposomes
(Stealth Technology)
o PEG coating
o Low permeability liquid matrix and
internal aqueous buffer system
Targeted liposomes
o Target specific ligands, such as
antibodies, immunoglobulins, lectins and
oligosaccharides attached to the surface
Cationic Liposomes
o Cationic lipid component interact with
negatively- charged DNA
o Results into Lipid –DNA Complexes
Temperature sensitive liposome
PH sensitive Liposomes
MANUFACTURING
OF
LIPOSOMES
Materials used in preparation
of liposomes
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Phospholipids
Synthetic Phospholipids
Glycerolipids
Sphingolipids
Glycosphingolipids
Steroids
Polymeric material
Charge-inducing lipids
Structure of phospholipids
Issues to consider when
selecting lipids.
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Phase transition temperature
Stability
Charge
Lipid mixtures
Cholesterol
Source
Preparation of Liposomes
Mechanism of Vesicle Formation
o The budding theory
o The bilayer phospholipids theory
The budding theory
o Stress induced hydration of phospholipids
o Organization in to lamellar arrays
o Results in to budding of lipid bilayer leading to down
sizing
SUV
OLV
The bilayer phospholipids
theory
o Liposomes are formed when thin lipid films are hydrated
o The hydrated lipid sheets detach during agitation and
self-close to form large, multilamellar vesicles (LMV)
Method
of
Liposome Preparation
Conventional liposome preparation methods
Phospholipids
Cholesterol
Antioxidant
Lipid component
compounding
Pyrogen
yes
Lipid solvent
Drug ,Salt
Antioxidant
Buffer
WFI
Ultrafilter
Filter
No
Filter
Solvent
recovery
Solvent
removal
Hydration
Extrusion
Down sizing
Free drug
recovery
Free drug removal
Prefilter
Sterile filter
Vial filling
Aseptic processing
Lyophollization
Seal / package
Method for preparation of (SUV)
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Sonication
High shear fragmentation
Solvent injection method
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Injection of water immiscible solvent.
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Ether infusion.
Fluorocarbon injection.
Injection of water miscible solvent.
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Ethanol injection
Modified ethanol injection method
High shear fragmentation
Piston
Cell body
Rubber-O-ring
Pressure relief valve
Aqueous
samples
Closure plug
Fig. French pressure
cell
Outlet
Solvent injection method.
Ether/lipid
solution
Vacuum
pump
Gasket
Mix
Aqueous
phase
Temperature
Controlled
bath
Mechanical drive
Infusion pump
Large and Intermediate sized
unilamellar vesicles.
o Methods used to prepare LUV and IUV
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Detergent dialysis
Water in oil emulsion technique
Freeze thaw cycling
Slow swelling in non electrolytes
Dehydration followed by rehydration
Dilution or dialysis of lipids in the presence
of chaotropic ions.
Reverse phase evaporation technique.
Lipid in solvent
solution
REV liposomes
Two-phase system
Gel formation
Water in oil
emulsion
Solvent removal
High pressure extrusion.
Methods for controlling liposome size
o Fractionation
o Centrifugation
o Size exclusion chromatography
o Homogenization
o Capillary pore membrane extrusion
o Ceramic extrusion
Liposome characterization and control
Liposomes
Characterized by
Size
Number of
lamellae
Stability
Charge
Determined by
Preparation
Raw
materials
Protection
Classified by
Hydration
methods
Sizing
method
Degree of
saturation
Head
group
Presence
of sterols
Protecting
agents
Physical characterization parameters
o Mean size and size distribution
o Number of lamellae
o Osmotic behavior and entrapped volume
o Internal distribution of drug
o Structural and motional behavior of lipids
o Electrical surface potential & Surface PH
Stability consideration
o Stabilization aspect for physical
instability of liposomes
o Chemical stability
o Biological stability of liposomes
Regulatory aspects
o Safety concerns: liposome formulation
o Lipid toxicity (RBC lysis)
o Presence of protein and lipoprotein for
natural lipids
o Residual solvent
o Overload of RES
o Particle size
o (tail above 1 um) - Blockage of capillaries
o Size affects RES uptake and tissue targeting
o Stability: shelf-live and in vivo
o Dose dumping (via protein binding)
o Sterility
Drug release from liposomes
o The lipid bilayer of the liposome can fuse
with other bilayers (e.g. cell membrane)
thus delivering the liposome contents.
Liposome Performance
– In Vitro Release and Stability
o In vitro drug release from liposomal
systems was determined using
dialysis sacks.
o Release test for a targeted liposome
would need to show that liposome is
stable until uptake at the site.
Factors affecting release of drug
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Solvents
pH
Temperature
Agitation
Enzymes
Cell culture
Sink conditions
Volume
Sampling interval
Applications
o Liposomes as Protein Carriers in
Immunology
o Oral Drug Delivery
o Site Specific Delivery
o Sustained or Controlled Delivery
o Gene Therapeutics
Applications
Innovations in vesicular drug
delivery systems
o Provesicles in drug delivery systems
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Provesicles in drug delivery systems
Proliposomes :Dry granular liposomes
Mixed micellar proliposomes
Protransferosomes
Characterization of provesicular system
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Morphology
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Angle of repose
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Size and size distribution
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Rate of hydration
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Entrapment efficiency
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Degree of deformability and
permeability measurement
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In vitro release rate
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In vivo fate and pharmacokinetic
Lipopolyplexes
o A combination of DNA, polymers
and liposomes
o This method has resulted in better
gene transfer and lower toxicity as
compare to cationic liposomes
Transferosomes
o Modified liposomes developed to increase
the transdermal permeation of drug
o Deformability is achieved by using
surface active agent in proper ratio
o Concentration of surfactant is very
crucial
Ethosomes
o Composed of phospholipids & alcohol
( ethanol or IPA)
o Sometimes polyols or glycols in
relatively high concentration & water
o Better membrane permeability
o Discomes
o Virosomes
o Emulsomes
Cochleates
o Cochleates are cigar-like microstructures
o Consist of a series of lipid bilayers which are
formed as a result of the condensation of small
unilamellar negatively charged liposomes.
Depofoam technology
o Depofoam particles include hundred of bilayer enclosed
aqueous compound.
o Formed by first emulsifying a mixture of an aq phase
containing the compound to be encapsulated & an
organic phase containing lipid.
Niosomes
o Nonionic surfactant vesicles(NSV)
o Niosomes are formed from the self assembly of non-ionic
amphiphiles in aqueous media resulting in closed bilayer.
Preparation of Liposomes by
dry film method
o Lipids and drug dissolved in CHCl3
and evaporated to form thin film
o Film is hydrated with buffer solution
o Sonicated to form large unilamellar
vesicles
Preparation of Liposomes by
dry film method
Lipid +
drug +
CHCl3
Rotary
evaporation
Sonication
LUV
Thin film
Approved liposome products marketed in US
Doxil
Daunorubicin
Alza Corporation
Kopasi sarcoma
Daunoxome
Daunorubicin
Gilead sciences
,,
Ambisome
Amphotericin B
,,
Serious fungal
infection
Approved lipid complex products
Ambelcet
Amphotec
Amphotericin B
Amphotericin B
Alza corporation
Elan corporation
NANOTECHNOLOGY
IN
DRUG DELIVERY
List of contents
o
INTRODUCTION
o
NANOPARTICLES
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History
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Types of nanoparticles
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Materials and methods
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Method of preparation for Nanoparticles
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Drug loading into nanoparticles
NANOSUSPENSION
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Method of preparation for Nanosuspension
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Purification of Nanosuspension
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CHARACTERIZATION AND EVALUATION OF
o
NANOPARTICLES AND NANOSUSPENSION.
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APPLICATIONS OF NANOPARTICLES AND NANOSUSPENSIONS
o
NANOSUSPENSION BASED FORMULATION IN DEVELOPMENT AND IN
THE MARKET
INTRODUCTION
o NANOSUSPENSIONS :
o are colloidal dispersions of nano sized
drug particle that are produced by
suitable method and stabilized by
suitable stabilizer .
o NANOPARTICLES :
o They are solid colloidal particles
sized from 1-1000 nm .
o NANOSPHERES :
o polymer matrices in which drug is
dissolved or dispersed .
o NANOCAPSULES :
o consists of polymer wall entrapping
an oily core in which the drug is
dissolved
History
o Developed by spieser and co-workers in the late
1960s.
o In early 1970s the cross linked polyacrylamide
nanoparticles were produced.
o Widder at el incorporated magnetic particles
into the nanoparticles for targeting of these
particles by means of magnetic field.
Types of nanoparticles
o Monolithic type
o Capsule type
Monolithic type
Capsule type
Polymers used in preparation.
o Polymethyl methacrylate copolymers,
o Polymethyl cyanoacrylate,
o Polybutyl cyanoacrylate & Polyisobutyl cyanoacrylate,
o Polyhexyl cyanoacrylate & polyisohexyl cyanoacrylate,
o Poly(Nα,N-L-lysinedylterephthalamide
o Polyisobutyl cyanoacrylate
o Poly-D,L-lactide
o Serum albumin
o Gelatin
o Polyacryl dextran
o Polyacryl starch
o Albumin
o Polylactic acid-poly glycolic acid copolymer
o Poly(-hydroxy butyrate)
o Ethyl cellulose
o Eudragit RL,RS
Method of preparation for
Nanoparticles
o Emulsion polymerization
o Continuous aqueous phase
o One of the most rapid method
o The monomer is dissolved in an aqueous phase
o The polymerization process is initiated by radiation, UV, or strong visible light
o Continuous organic phase
Denaturation of natural molecules
in an oil emulsion.
o Requires emulsification of a natural
macromolecule and the drug
o The particles are hardened by
o Heat denaturation,
o Cooing below the gelation point,
o Cross-linking with suitable reagent.
o Disolvation of macromolecules.
o This process is commonly known as
coacervation.
o Solvent evaporation
Drug loading into nanoparticles
o Drug may be loaded at two stageso Prior to the preparation of
nanoparticles
o Addition to the previously prepared
particles
NANOSUSPENSION
o Colloidal dispersions of nanosized
drug particle produced by
suitable method and stabilized by
suitable stabilizer .
Method of preparation for
Nanosuspension
o Media milling (Nanocrystals)
Milling chamber
Milling Shaft
Drug, water
& stabilizer
Screen retaining
milling media in
chamber
Milling media
High Pressure Homogenizers
o Size reduction depends upon:
o Homogenization pressure
o No. of homogenization cycle
CHARACTERIZATION
AND
EVALUATION
Physicochemical Characterization
o Particle size
o Molecular Weight Density
o Crystallinity
o Surface charge
o Hydrophobicity
o Surface properties
o Surface element analysis
Drug release
o Side by side diffusion cells with artificial
or biological membrane.
o Dialysis bag diffusion
o Reverse dialysis
o Ultra centrifugation
o Ultra filtration
o Gel filtration
o Centrifugal Ultra filtration
APPLICATIONS
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Oral Drug Delivery
Parenteral Drug Delivery
Ocular Drug Delivery
Pulmonary drug delivery
Targeted drug delivery
NANOSUSPENSION BASED
FORMULATION
Drug
Status
Paclitaxel
Phase III
Rapamune
Marketed
Emend
Marketed
Cytokine Inhibitor
Phase II
Thymectacin
Phase I & II
Busulfan
Phase I
Budesonide
Phase I
References
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A.D. Bangham , J. Mol. Biol. 13:238-252, 1965
Ali Demir Sezer,Ahmet Levent Bas, and Ju¨ lide Akbug,
Encapsulation of Enrofloxacin in Liposomes I: Preparation
and In Vitro Characterization of LUV, Journal of liposome
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Kamps, Liposome Opsonization, Journal of Liposome
Research, 15:109–139, 2005
Ilya Koltover, Tim Salditt, Joachim O. Radler, An Inverted
Hexagonal Phase of Cationic Liposome±DNA Complexes
Related to DNA Release and Delivery, 3 July 1998, vol.281
SCIENCE,www.sciencemeg.org
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Sonobe, Effect of Polyethyleneglycol (PEG) Chain on Cell
Uptake of PEG-Modified Liposomes Journal Of Liposome
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References
o
o
o
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Lee Leserman, Liposomes as Protein Carriers in
Immunology, Journal Of Liposome Research, Vol. 14, Nos. 3
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of plasmid DNA to hepatotoxicity after systemic
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696.
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References
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o
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Andreas Wagner, Karola Vorauer-Uhl, Gunther Kreismayr,
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2002.
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dispersions, Int. J. Pharm., 50, 1, 1989.
References
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Yoshie Maitani, Hiroshi Soeda, Wan Junping, And Kozo
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Shangguan et.al , 2000, Gene Ther., 7, 769.
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