1. LIPOSOMES AND
NANOPARTICLES
Presented by
G.PAVANI.
256212886011
M.Pharm-Pharmaceutics

2. Contents of liposomes
Introduction
Mechanism of liposome formation.
Classification.
Methods of preparation.
Characterization.
Stability.
Applications and Commercial products.

3. introduction
DEFINITION:
Liposomes are targeted drug delivery systems consisting of one or
more concentric spheres of lipid bilayers separated by water or
aqueous buffer compartments composed of natural or synthetic
phospholipids .
HYDROPHOBIC
HYDROPHILIC

4. ADVANTAGES:
Selective passive targeting to tumour tissue.
eg: liposomal Doxorubicin.
Enhanced efficacy and therapeutic index.
Decreased toxicity.
Site avoidance effect.
Improved pharmacokinetic effects.
Flexibility to couple with site specific ligands to achieve active
targeting.

5. DISADVANTAGES:
Less stability.
High production cost.
Phospholipid hydrolysis.
Phospholipid oxidation.
Leakage and fusion.
Allergic reaction may occur with liposomal constituents.

6. STRUCTURAL COMPOSITION OF LIPOSOME:
The main components are:
Phospholipids
eg: phosphatidylethanolamine.
phosphatidylcholine.
phosphatidylglycerol.
phosphatidyllinositol.
cholesterol

7. Generally phospholipids are represented as follows:

8. PHOSPHOLIPIDS:
Phospholipids are the major structural components of the
biological membrane such as cell membrane.

9. CHOLESTEROL:
Cholesterol by itself does not form a lipid bilayer.
However cholesterol acts as fluidity buffer.
It is incorporated in the membrane at very high concentration in the
ratio up to 1:1or 2:1 molar ratios of cholesterol to PC.

10. MECHANISM OF LIPOSOMAL FORMATION

16. MECHANICAL DISPERSION:
Lipid film hydration by hand shaking/non hand
shaking:

17. Micro-emulsification:

18. Sonication:

19. French pressure cell:

21. Dried reconstituted vesicles and freeze thaw sonication:

22. SOLVENT DISPERSION:
Ethanol and Ether injection:

23. Double emulsion vesicles:
The organic solution, which already contains water droplets is
introduced in to excess aqueous medium followed by mechanical
dispersion.
 The W/O/W double emulsion is formed.
Two aqueous compartments being separated from each other by a
phospholipid monolayer.
Removal of solvent results in an intermediated sized unilamellar
vesicles and entrapment is up to 90%.

24. Reverse phase evaporation vesicles:

25. DETERGENT DEPLETION(REMOVAL) METHODS:
Detergents associate with the phospholipid molecules and serve to
screen the hydrophobic portions of of molecule from water.
The structures formed as a result of this association is known as
micelles.
A three stage model of interaction for detergents with lipid bilayers:
Stage1: At low concentration detergents equilibrates between
vesicular lipid and water phase.
stage2: After reaching a critical detergent concentration, membrane
structure tends to unstable and transforms gradually in to micelles.
stage3: All lipid exists in mixed micelle form.
Three methods are applied for removal of detergent and transition
of mixed micelles to concentric bilayered form.

26. DIALYSIS:
The molecules of detergent are removed from mixed micelle by
dialysis by lowering the concentration of detergent in bulk aqueous
phase.
eg: sodium cholate.
octylglucoside.
COLUMN CHROMATOGRAPHY:
Removal of detergent is achieved by by passing the dispersion over
a sephadexg-25 column pre-saturated with constitutive lipids and
pre-equilibrated with hydrating buffer.
eg: deoxycholate.

27. Remote(active) loading:

28. Removal of unentrapped drug from liposomes:
It is important to estimate the amount of drug encapsulated within
liposomes.
This is easier to estimate by centrifugation in case of MLVs
compared to LUVs and SUVs.
The various methods used to separate non-encapsulated drug are
eg: Dialysis.
Gel chromatography.

29. Characterization
VESICLE SIZE AND SIZE DISTRIBUTION:
Microscopy .
Gel chromatography.
LAMELLARITY:
Freeze fracture and freeze-etch electron microscopy.
31 P NMR analysis.
SURFACE CHARGE:
Free flow electrophoresis
Zeta potential method.

30. ENCAPSULATION EFFICIENCY:
The encapsulation efficiency describes the percent of drug that
becomes ultimately entrapped during preparation of liposomes.
 It is expressed as %entrapment/mg lipid.
It is assessed by two techniques:
Minicolumn centrifugation.
Protamine aggregation.

31. TRAP PED VOLUME:
The internal or trapped volume is the aqueous entrapped volume per
unit quantity of lipid and expressed as μl/mol.
The entrapped volume is determined using various materials like
inert fluid-D2O, radioactive markers- 22Na or 14C and fluorescent
markers- 6-carboxyfluorescein.
PHASE BEHAVIOR OF LIPOSOMES:
Membrane phospholipids undergo temperature dependent reversible
phase transitions from gel to liquid crystaline state.
These have been documented by freeze fracture electron
microscopy and DSC.
Tm of the phospholipid affects the membrane permeability, leakage
and stability of liposomes.
Tm can be altered by using phospholipid mixtures or by adding
cholesterol.

32. INVITRO DRUG RELEASE
It is done by dialysis bag.
CHEMICAL CHARACTERIZATION:
PARAMETERS ANALYTICAL METHOD
Phospholipid concentration Barlett assay/stewart assay, HPLC
Cholesterol concentration Cholesterol oxidase assay,HPLC
Phospholipid hydrolysis HPLC,TLC and Fatty acid concentration
Phospholipid oxidation UV and GLC

33. STABILITY
STABILITY in vitro:
Lipid oxidation and peroxidation
Lipid hydrolysis
Long term and Accelerated stability.
STABILITY in vivo:
Stability after systemic administration.
Stability after oral administration.

34. MODES OF LIPOSOME AND CELL INTERACTION:
Adsorption Endocytosis
Fusion Lipid transfer

35. APPLICATIONS
Liposomes as drug or protein delivery vehicles.
Liposome in antimicrobial, antifungal(lung therapeutics) and
antiviral (anti HIV) therapy.
In tumour therapy.
In gene therapy.
In immunology.
Liposomes as artificial blood surrogates.
Liposomes as radiopharmaceutical and radiodiagnostic carriers.
Liposomes in cosmetics and dermatology.

36. COMMERCIAL PRODUCTS
Doxorubicin(DOXIL).
Daunorubicin(DAUNOXOME).
AmphotericinB(APHOTEC, AMBISOME,
ABELCET).
Cytarabine(DEPOCYTE).

37. CONTENTS OF NANOPARTICLES Introduction
Preparation methods.
Novel nanoparticulate system.
Surface engineering of nanoparticles.
Characterization.
Applications.
Commercial products.

38. INTRODUCTION
DEFINITION:
Nanoparticles are sub- nano sized colloidal structures composed
of synthetic or semi synthetic polymers with a size smaller than
1mm.
The term nanoparticles include
NANOSPHERE NANOCAPSULE

39. ADVANTAGES:
Easy manipulation of Particle size and surface characteristics.
They control and sustain release of the drug.
Drug loading is relatively high.
Incorporation of drug without any chemical reaction.
 Site-specific targeting(ligands)
 Administrations including oral, nasal, parentral, intra-ocular etc

40. DISADVANTGES:
High cost
Productivity more difficult
Reduced ability to adjust the dose
Highly sophisticated technology
Requires skills to manufacture

41. POLYMERS:
Natural polymers:
PROTEINS POLYSACCHARIDES
Gelatin Alginate
Albumin Dextran
Lectins Chitosan
Legumin Agarose
vicilin pullulan
Synthetic polymers:
PRE- POLYMERIZED POLYMERIZED IN PROCESS
Poly(Ɛ-caprolactone) Poly(isobutylcyanoacrylates)
Poly lactic acid Poly(butylcyanoacrylate)
Ploy(lactic-co-glycolide) Polyhexylcyanoacrylate
polystyrene Poly methyl methacrylate

42. METHODS OF PREPARATION
Amphiphilic
macromolecule
crosslinking
Polymerization
based methods
Ploymer
precipitation
methods
•Heat cros-linking.
•Chemical cross-linking
•Polymerization of monomers.
•Emulsion polymerization.
•Dispersion polymerization.
•Interfacial condensation
polymerization.
•Interfacial complexation.
•Solvent
extraction/evaporation.
•Solvent displacement
or nanoprecipitation.
•Salting out.

43. MACROMOLECULAR CROSS LINKING IN A WATER IN
OIL EMULSION:
aAqueous
protein
(BSA)
O
oil
or hEmulsification using high-pressure
homogenization/ high
frequency sonication
W/O emulsion
Dilution with preheated oil (100oC)
(Heat cross-linking)
Or Addition of crosslinking agent
(Chemical cross-linking)
Centrifugation and isolation of
nanoparticles
surfactant

44. POLYMERIZATION OF MONOMERS:
Water+ monomer A Oli phase
High pressure homogenization
w/o emulsion.
Nanocapsules.
Monomer B

45. MICELLAR PLOYMERIZATION MECHANISM:

46. HOMOGENOUS POLYMERIZATION MECHANISM:

47. DISPERSION POLYMERIZATION:
(Acrylamide or Methyl methacrylate) Monomer is dissolved
in an aqueous medium
Further, By chemical initiation
(ammonium or potassium per oxo disulphate)
Heated to above 65 C
Oligomers aggregate &
precipitates
lsolation of nanospheres
47

48. INTERFACIAL POLYMER CONDENSATION:
Core phase + drug Ploymer phase
o/w emulsion.
Nanocapsules.
(30-300nm)
Non-solvent which precipitate
polymer from either of the phases

49. INTERFACIAL COMPLEXATION:
Polyelectrolyte. Reverse micelle
nanoparticles.
Competing polyelectrolyte
Polymer complexation

50. SOLVENT EVAPORATION METHOD:
Organic phase solvent,
drug, polymer.
Aqueous phase distilled
water, stabilizer.
Sonication, homogenization
o/w emulsion
Solvent extraction, solvent evaporation.
Nanoparticles.

51. Double emulsion solvent evaporation method:
Organic phase solvent,
drug, polymer.
Aqueous phase
distilled water,
Stabilizer.
Sonication, homogenization
w/o emulsion
stabilized at 4oc
w/o/w emulsion.
Nanoparticles.
Aqueous phase with stabilizer
Solvent extraction, solvent evaporation

52. SOLVENT DISPLACEMENT METHOD:
Distilled water,
polaxamer 188
Distilled water,
polaxamer
188
Organic solvent,
polymer, drug
Polar solvent, oil,
polymer, drug.
Magnetic stirring
Nanospheres. Nanocapsules.

53. SALTING OUT:
Nanoparticle.
Distilled water,
PVA, MgCl2
Organic solvent,
drug, polymer.
o/w emulsion.
Mechanical stirring
Distilled water

54. PHARMACEUTICAL ASPECTS OF NANOPARTICLES:
Purification:
Dialysis.
Gelfiltration.
Ultra-centrifugation.
Freeze drying.
Sterilization.

55. NOVEL NANOPARTICULATE SYSTEM
SOLID LIPID NANOPARTICLES:
Solid lipid nanoparticles are sub micron colloidal carriers
composed of physiological lipid dispersed in water or in aqueous
surfactant solution.
Advantages:
SLN Can be lyophilized as well as spray dried.
No toxic metabolites are produced.
Avoidance of organic solvents.
COPOLYMERIZED PEPTIDE NANOPARTICLES:
It is a drug polymer conjugate which forms its own nanoparticulate
drug delivery system.
eg: n-butylcyanoacrylate

56. HYDROGEL NANOPARTICLES:
Hydrogel nanoparticles are formed in the water by self-assemblage
and self aggregation of natural polymer amphiphiles.
eg:cholesteroyl dextran.
cholesteroyl pullan.
NANOCRYSTALS AND NANOSUSPENSIONS:
Nanocrystals are produced by dispersion of the drug powder in the
surfactant solution and subjecting to the pearl milling process.
Nanosuspensions are produced by dispersion of drug powder in
aqueous surfactant solution by high speed stirring which is then
passed through high speed homogenizer leading to formation of
nanosuspension.

57. SURFACE ENGINEERED NANOPARTICLES
STEARICALLY STABILIZED (STEALTH) NAOPARTICLES:
The surface modification of particulate carriers is achieved by
coating or grafting to nanoparticle surface with certain materials that
impart stealth behaviour.
eg:Polaxamers.
Polaxamines.
BIO-MIMETIC NANOPARTICLES:
These are the nanoparticles coated with endogenous serum
components which prevent their uptake through mononuclear
phagocytic system.
eg:Albumin.
Orosomucoid.

58. NANOPARTICLES COATED WITH ANTIBODIES:
Anchoring of targeted specific antibodies to the nanoparticle
surface may facilitate the delivery to specific sites.
eg: Monoclonal antibodies.
MAGNETIC NANOPARTICLES:
Nanoparticles are rendered magnetic by incorporating Fe3O4
simultaneously with drug during the preparation stage, injected
through the artery is guided by the external magnet inorder to target
the site.
BIOADHESIVE NANOPARTUCLES:
Drugs are associated to polymeric bioadhesive nanoprticulate system
as they adhere to the mucosal surface provide better drug absorption.
eg: lectin.

59. CHARACTERIZATION
PARTICLE SIZE AND SIZE DISTRIBUTION:
Photon correlation spectroscopy.
Scanning electron microscopy.
Transmission electron spectroscopy.
SURFACE CHARGE:
The surface charge of nanoparticle is determined by measuring the
particle velocity in an electric field.
Laser Doppler Anemometry.
SURFACE HYDROPHOBICITY:
Hydrophobic interaction chromatography.
 Two phase partitioning technique.

60. MOLECULAR WEIGHT OF POLYMER CARRIER:
Different ways to express molecular weight is number average
weight (Mn) and weight average molecular weight (MW).
gel permeation chromatography.
PHYSICOCHEMICAL STATE OF DRUG AND POLYMER:
Thermal analysis.
X-ray Diffraction.
DRUG LOADING:
Ultra centrifugation.
Ultra filtration.
Gel filtration.

61. DRUG INCORPORATION EFFICIENCY:
IN VITRO DRUG RELEASE:
PH 1.2 HCl buffer.
Phosphate buffer PH 5.
Phosphate buffer PH 6.8

62. APPLICATIONS
Nanoparticles in chemotherapy.
Nanoparticles in intracellular targeting.
Nanoparticles for ocular and brain delivery.
Nanoparticles for DNA delivery.
Nanoparticles for oligonucleotide delivery.
Nanoparticles for lymph targeting.
Nanoparticles for peroral administration of protein and peptide.

63. COMMERCIAL PRODUCTS DaunoxomeR - Anticancer.
GendicineR – Gene delivery.
AmphoteR – Antifungal.
.
AmbraxaneR – Anticancer.
DoxilR - Anticancer
Nanoxel.

64. CONCLUSION
Liposome over the years have been investigated as major drug
delivery system.
The use of liposomes in delivery of drugs and genes to tumour
site are promising and may serve as a handle for focus of future
research.
Nanoparticles are have been used as a drug carrier in
transdermal formulations to enhance absorption of therapeutic
agents.
With advent of novel nanoparticulate systems the
nanoparticulate technology seems to dominate the field of drug
delivery and drug targeting in future.

65. REFERENCE
Deepak Thassu, Michel Deleers, “Nanoparticulate Drug delivery
systems,” vol-166. pg.no:89.
Herbert A.Lieberman, Martin M.Rieger and Gilbert S.Banker,
“Pharmaceutical dosage forms: Disperse systems,” vol-3. 2nd edition.
Pg.no:43-83 & 87-119.
S.P.Vyas, R.K.Khar, “ Targeted & Controlled Drug Delivery,”
edition-2006. pg.no:173-243 & 331-381.
Nepolean R, Narayanan.N, “Journal of pharmaceutical sciences and
technology,” academic reaserch publication. Vol-4.pg.no:83-84.
Mohamed Badran, Abdelaziz Elsayed, “Asian journal of
pharmaceutical & Health science,” vol-3. pg.no:640-641.