LIPOSOMES & NIOSOMES

DEPARTMENT OF PHARMACEUTICS

S.R.R COLLEGE OF PHARMACEUTICAL SCIENCES

ELAKATHURTHY(M),VALBHAPUR(V),KARIMNAGAR

Presented by;

AITHA SWETHAM.PHARMACY 1ST YEAR 2ND SEM

• Introduction• Structure of liposomes • Advantages& disadvantages• Components of liposome• Mechanism of liposome• Preparation methods of liposomes• Characterization of liposomes• Applications of liposomes • Summary• Niosomes Introduction • Advantages& disadvantages• Preparation methods of niosomes• Characterisation of niosomes• summary

• References

CONTENTS:

LIPOSOMES

liposomes are concentric bilayered

vesicles in which an aqueous volume is

entirely enclosed  by a membraneous

lipid bilayer mainly composed of natural

or synthetic phospholipids.Liposomes were first produced in England in 1961 by

Alec D. Bangham. The size of a liposome ranges from some

20 nm up to several micrometers

1

Structure Of Liposome

Hydrophillic headHydrophobic tail

The lipid moecules are usually

phospholipids-amphipathic

moieties with a hydrophilic head group

and two hydrophobic tails.

Liposome =Phospholipid+ cholesterol

2

Provides selective passive targeting t

o tumor tissues.

(liposomal doxorubicin) .

Increased efficacy and therapeutic in

dex.

Reduction in toxicity of the encapsula

ted agent.

Site avoidance effect (avoids non-

target tissues).

Improved pharmacokinetic effects .

Flexibility to couple with site-

specific ligands to achieve 

active targeting.

Advantages of liposomes:

3

Disadvantages of liposomes:

Production cost is high.

Leakage and fusion of

encapsulated drug /

molecules.

Sometimes phospholipid

undergoes oxidation and

hydrolysis like reaction.

Short half-life.

Low solubility.

4

H2O Layer

Polar Lipids

(Phospholipid)

Water Soluble ingredients(Drugs, Nutrients

& vitamins)

Lipid Soluble ingredients(Drugs,Nutrients & vitamins)

Cross-section of liposomes:

5

components of liposomes:

The structural components of

liposomes include:

A. Phospholipids

B. cholesterol

6

A. General representation of phospholipids:

7

Phospholipids

Phosphatidylcholine- natural

Amphipathic molecule Hydrophilic polar head-

Phosphoric acid bound to water soluble molecule.

Glyceryl bridge Hydrophobic tail-

2 fatty acid chain containing 10-24 carbon atoms and 0-6 double bond in each chain.

The amphipathic molecule self organise in ordered supramolecular structure when confronted (meet face to face) with solvent.

8

The most common natural phospholipid

is the phospatidylcholine (PC ).

Naturally occurring phospholipids

used are :

PC: Phosphatidylcholine.

PE: Phosphatidylethanolamine.

PS: Phosphatidylserine

Synthetic phospholipids used are:

DOPC: Dioleoyl phosphatidylcholine

DSPC: Disteroyl

phosphatidylcholine

DOPE: Dioleoyl

phosphatidylethanolamine

DSPE: Distearoyl

phosphatidylethanolamine

Polar Head Groups

Three carbon glycerol

9

Molecular geometry on structure of amphiphillic aggregates:

10

Molecules of PC are not soluble in water.

In aqueous media they align themselves close

ly in planar bilayer sheets 

in order to minimize the 

unfavorable action between the bulk aqueous 

phase and the long hydrocarbon fatty chain. 

Such unfavorable interactions are completely

eliminated when the

sheets fold on themselves to form closed

sealed vesicles

11

At various temperatures, phospholipid membranes can exist in different phases. The transition from one phase to another can be detected by technique like micro calorimetry . What exactly happens during phase transition?

Tightly ordered At elevated temperature liquid crystal phase gel state ( lipid membrane) (movement is higher) This is due to the fatty acid chain adopting a new conformation other than all trans straight chain configuration, such as gauche configuration state( phenomenon- chain tilt )

PHASE TRANSITION TEMPERATURE

12

B. Cholesterol:

Cholesterol stabilizes the Membrane

Steroid lipid

Interdigitates between phospholipids.

i.e. below Tc , it makes membrane less

ordered & above Tc more ordered.

Being an amphipathic molecule, cholesterol inserts into the membrane with its hydroxyl group of cholesterol oriented towards the aqueous surface and aliphatic chain aligned parallel to the acyl chains in the center of the bilayer .

13

Role of cholesterol in bilayer formation:

Cholesterol act as fluidity bufferAfter intercalation with

phospholipid molecules alter the freedom of motion of carbon

molecules in the acyl ChainRestricts the transformations of

trans to gauche Conformations.Incorporated into phospholipid

membrane upto 1:1 or 2:1 of cholesterol to PC.

14

Mechanism of liposome formation:

15

Classification of liposome :

Classification of liposome

Structural parameters

Method of preparation

Composition and application

16

Types of vesicles based on lamella

Lamella :

17

Based on structural  parameters

MLVMultilam

ellar Large

vesicles(>0.5 um)

OLV oligolamellar

vesicles(>0.1-1.0

um)

UV Unilam

ellarVesicle

s 

MVVMultivesicularvesicles

(> 1.0 UM)

MUV

GUV>1um

SUV20-

100nmLUV>100n

m

A. Structural parameters:

18

Based on

method of

preparation

REV, SUV made by reverse phase

evaporation

method

SPLVStable plurilamenar vesicle

s

FATMLVFrozen

& thawed

MLV

VETVesicle

s prepare

d by extrusi

on tech.

B. Based on method of preparation:

19

Based on

composition &

application

conventia

l

fusogenic

pH sensitive

cationic

Long circulatory

immuno

Based on composition and application:

20

Passive loading

technique

Active/remote loading

technique

Loading of the entrapped agents before/ during the manufacture procedure.

Certain types of compounds with ionizable groups & those with both lipid & water solubility can be Introduced into liposomes after the formation of intact vesicles.

MethodS of Liposome Preparation

21

LIPID FILM HYDRATION BY HAND SHAKING,FREEZE DRYING OR NON HAND SHAKING

MICRO EMULSIFICATION

SONICATION

FRENCH PRESSURE CELL

MEMBRANE EXTRUSON

DRIED RECONSTITUTED VESICLES

ETHANOL INJECTION

ETHER INJECTION

DOUBLE EMULSION

REVERSE PHASE

VAPOURATION VESICLES

STABLE PLURI LAMELLER

VESICLES

DETERGENT REMOVAL

FORM MIXED MICELLES

BY DIALYSIS

CHROMATIGRALPY

DIFFUSION

VESICLES LIKE….

RECONSTITUTED &

SANDAI VIRUS ENVELOPE

Methods of liposome preparation

Passive loading techniques

Active loading techniques

Mechanical dispersion  methods

Solvent dispersion  methods

Detergent removal technique

22

General Method Of Liposome Preparation:

23

1. Mechanical dispersion method:

24

There are four basic methods of

physical/mechanical dispersion :

Hand shaken method.

Non shaking method.

Pro – liposomes .

Freeze drying .

25

Lipid film hydration by hand shaking method:

Lipids form stacks of film from organic solution (FE/HS)Then film is treated with aqueous medium

Upon hydration lipids swell and peel out from RB flask

vesiculate to form Multi lamellar vesicles(MLVs)

26

Pro-liposomes:

To increase the surface area of dried lipid film & to facilitate instantaneous hydration.lipid Dried

over

lipid

Finely divided

particulate support like powdered

NACL/ sorbital

Pro - liposomes

Pro- liposomes

water

Dispersion of MLV’S

This Method overcome the stability problem.

27

Micro Emulsification liposomes (MEL)

Sonicated unilamellar vesicles (SUVs)

French Pressure Cell Liposomes .

Membrane extrusion Liposomes

Dried reconstituted vesicles(DRVs)

Freeze thaw sonification (FTS)

pH induced vesiculation

Cochleate method.

Processing of the lipids hydrated by

physical means or the mechanical

treatments of MLVs :

28

Sonicated unilamellar vesicles:

The exposure of MLVs to ultrasonic irradation for producing small vesicles.

Probe sonicator Bath sonicatorUsed for dispersions large volume require high of dilute lipidsenergy insmall volumes

SonicationMLVs hazy transparent 5-10 min solution centrifugation 30 min

clear SUV Dispersion.

29

Micro emulsification liposomes:

Micro fluidizer 30

French pressure cell liposomes:

Extrusion of preformed large liposomes in french press under very high pressure .

uni or oligo lamellar liposomes of intermediate size (30-80nm ) .

Advantages Less leakage and more stable liposomes are formed compared to sonicated forms

31

Vesicles prepared by extrusion technique :

The size of liposomes is reduced by gently passing them through polycarbonate membrane filter of defined pore size at lower pressure

Used for preparation of LUVs and MLVs

32

Dried reconstituted vesicles& freeze thaw sonication method

33

pH induced vesiculation:

Preformed MLV’S(2.5-3.0)

Exposed to high pH~ (addition of 1M NaoH)~Period of exposure < 2min

Reduced the pH to 7.5* Addition of 0.1M Hcl

The transient change in pH brings about an increase in surface charge of the lipid bilayer which induces spontaneous vesiculation .

MLVs

LUVs

34

SUVs made from phosphatidylserine(PS)

Addition of Ca++ ions

Cylindrical rolls(cochleate cylinders)

Removal of Ca++ by EDTA

Cochleate method:

Cochleates

35

Note:- Organic solvent miscible with aqueous phase

Solvent dispersion methods:

36

Solvent dispersion methods:ETHANOL INJECTION/ETHER INJECTION:

37

De-Emulsification method:

Generally the liposome is made up

in 2 steps:

1 st the inner leaflet of the bilayer .

Then the outer half.

Methods to prepare the droplets: ~Double emulsion vesicles ~Reverse phase evaporation vesicles ~Sonication methods

Aqueous medium containing material to be entrapped

Add to immiscible organic solution of lipid

Mechanical agitation

Microscopic water droplets

38

Reverse phase evapouration method:

39

Note:- Liposome size and shape depend on chemical nature of detergent, concentration and other lipid involved

Below CMC, detergent molecules exist in free soln. As the concentration is increased, micelles are formed.

DETERGENT SOLUBILISATIOIN METHODS

Methods to remove detergents: Dialysis Column chromatography.

40

Active/remote loading technique:The lipid bilayer membrane is impermeable to

ions & hydrophilic molecules. But,

Permeation of hydrophobic molecules can be

controlled by concentration gradients.

Some weak acids or bases can be transported

due to various transmembrane gradients

Electrical gradients.

Ionic(pH) gradients.

Chemical potential gradients.

Weak amphipathic bases accumulate in

aq phase of lipid vesicles

in response to difference in pH b/w

Inside & outside of

liposomes 

41

pH gradient is created by preparing liposomes with low internal pH.

Addtn of base to extraliposomal medium.

[Basic compds ( lipophilic (non ionic) at high pH & hydrophilic(ionic) at low pH)]

Lipophilic (UNPROTONATED) drug diffuse through the bilayer

At low pH side, the molecules are predominantly protonated .

Exchange of external medium by gel extrusion chromatorapghy with neutral solution.

Weak bases like doxorubicine, adriamycin and vincristine are encapsulated.

Solute bearing no charge at neutral pH

Liposomes with low internal pH

Neutral solute passes easily through bilayer membrane by diffusion

Charge aquired by solute inside liposomes makes them unable to exit 42

Locus of drugs in liposomes:Hydrophilic (DOXORUBICIN) Low entrapment Leakage Hydrolytic degradation Lipophilic (CYCLOSPORINE)High entrapment Low leakage Chemical stability

Ampiphilic (VINBLASTIN) High entrapment Rapid leakage Biphasic insoluble (ALLOPURINOL, 6-MERCAPTOPURINE) Poor loading & entrapment

43

Characterization of liposomes:

PHYSICAL CHARACTERISATION

→ Vesicles size/shape/morphology

→ Surface -charge/electrical potential

→ Phase behaviour/ lamellarity

→ Drug release

→ % capture /free drug

CHEMICA L CHARACTERISATION

→ Phospholipids /lipid concentration

→ Drug concentration

→ PH / Osmomolality

→Antioxidant degradation

→ Phospholipids / cholesterols –

peroxidation/oxidation/hydrolysis

BIOLOGICAL CHARACTERISATION

→ Sterility

→ Pyrogenisity

→ Animal toxicity

→Plasma Stability: 44

Characterization parameters

Analytical method/Instrument

1. Vesicle shape and surface morphology

Transmission electron microscopy, Freeze-fracture electron microscopy

2.Mean vesicle size and size distribution (submicron and micron range)

Photon correlation spectroscopy, laser light scattering, gel permeation and gel exclusion

3. Surface charge Free-flow electrophoresis

4. Electrical surface potential and surface pH

Zetapotential measurements

5. Lamellarity Small angle X-ray scattering, 31 P-NMR, Freeze-fracture electron microscopy

6. Phase behavior Freeze-fracture

electron microscopy, Differential scanning calorimetery

7. Percent of free drug/ percent capture

Minicolumn centrifugation, ion-exchange chromatography, radio labelling

8. Drug release Diffusion cell/ dialysis

1.PHYSICAL CHARACTERIZATION:

45

Characterization parameters

Analytical method/Instrument

1. Phospholipid concentration

Barlett assay, stewart assay, HPLC

2. Cholesterol concentration

Cholesterol oxidase assay and HPLC

3. Phopholipid peroxidation

UV absorbance

4. Phospholipid hydrolysis,

Cholesterol auto-oxidation.

HPLC and TLC

5. Osmolarity Osmomete

2. CHEMICAL CHARACTERIZATION:

46

Characterization parameters Analytical method/Instrument

1. Sterility Aerobic or anaerobic cultures

2. Pyrogenicity Limulus Amebocyte Lysate (LAL) test

3. Animal toxicity Monitoring survival rates, histology and pathology

3. BIOLOGICAL CHARACTERIZATION:

STABILITY OF LIPOSOMES: Stability invitro . ~ Lipid oxidation ~ Lipid peroxidation ~ Long term & accelerated stability Stability after systemic administration.

47

MODES OF LIPOSOMES/CELL INTERACTION:

1. Endocytosis

2. Adsorption

3. fusion 4. Lipid transfer

48

• Encapsulation volume/Trapped volume Volume of aqueous solution entrapped in liposomes per mole

of PL (µL/µmol PL)• Encapsulation Efficiency Assessed by mini column centrifugation method & protamine

aggregation method. protamine aggregation method used for neutral and

negetively charged liposomes. Liposome dispersion can be precipitated with protamine solution and subsequent centrifugation at 2000RPM.

By analysing the material in super natent & in liposome pellet ( after disrupting liposomal pellet with 0.6 ml of 10% triton x-100 ). The encapsulation efficiency of entrapped material can be estimated.

• % Encapsulation

Drug entrapped in liposomes x 100 Total drug added

Encapsulation of drugs in liposomes:

49

In gene delivery.

As drug delivery carriers.

Enzyme replacement therapy.

Chelation therapy for treatment of heavy

metal poisoning.

Liposomes in antiviral/anti microbial

therapy.

In multi drug resistance.

In tumour therapy.

In immunology.

In cosmetology

USES OF LIPOSOMES :

50

DNA delivery of Genes by Liposomes

Cheaper than viruses

No immune response

Especially good for in-lung delivery (cystic fibrosis)

100-1000 times more plasmid DNA needed for the same transfer efficiency as for viral vector

51

Lipofection

52

Liposomes could serve as tumor specific vehicles (even without special targeting)

Liposomes better penetrate into tissues with disrupted endothelial lining 53

DRUG ROUTE OF ADMINISTRATION

APPLICATION TARGETED DISEASES

Amphotericin B Oral delivery Ergosterol membrane Mycotic infection

Insulin Oral,ocular,pulmonaryAnd transdermal

Decrease glucose level Diabetic mellitus

Ketoprofen Ocular delivary Cyclooxygenase enzyme inhibitor Pain muscle condition

Pentoxyfyllin Pulmonary delivery phosphodiesterase Asthama

Tobramycin Pulmonary delivery Protein synthesis inhibitor Pseudomonas infection,aeroginosa

Salbutamol Pulmonary delivery ß2-adrenoceptor antagonist Asthama

Cytarabin Pulmonary delivery DNA-polymerase inhibition Acute leukameias

Benzocaine Transdermal Inhibition of nerve impulse from sensory nerves

Ulcer on mucous surface with pain

Ketaconazole Transdermal Inhibit ergosterol membrane Candida albicans

Levanogesterol Transdermal Rhamnose receptor skin disorder

hydroxyzine Transdermal H1-receptor antagonist Urtecaria,allergic skin disease

Ibuprofen Oral delivery Chaemoceptor,free ending Rheumatoid arthritis

triamcilonone Ocular delivery,Transdermal Inhibition of prostaglandin Anti-inflammatory

Therapeutic application of liposomes:

54

NAME TRADE NAME COMPANY INDICATION

Liposomal amphotericin B

Abelcet Enzon Fungal infections

Liposomal amphotericin B

Ambisome Gilead Sciences Fungal and protozoal infections

Liposomal cytarabine Depocyt Pacira (formerlySkyePharma)

Malignant lymphomatous meningitis

Liposomal daunorubicin

DaunoXome Gilead Sciences HIV-related Kaposi’s sarcoma

Liposomal doxorubicin Myocet Zeneus Combination therapy with cyclophosphamide in metastatic breast cancer

Liposomal IRIV vaccine Epaxal Berna Biotech Hepatitis A

Liposomal IRIV vaccine Inflexal V Berna Biotech Influenza

Liposomal morphine DepoDur SkyePharma, Endo Postsurgical analgesia

Liposomal verteporfin Visudyne QLT, Novartis Age-related macular degeneration, pathologic myopia, ocularhistoplasmosis

Liposome-PEGdoxorubicin

Doxil/Caelyx Ortho Biotech,Schering-Plough

HIV-related Kaposi’s sarcoma, metastatic breast cancer, metastaticovarian cancer

Micellular estradiol Estrasorb Novavax Menopausal therapy

List of marketed products :

55

summary:

o liposomes are concentric bilayered vesicles

in which an aqueous

volume is entirely enclosed

 by a membraneous lipid bilayer

o Liposomes are one of the unique drug

delivery system, in controlling

and targeting drug delivery.

o Components of liposomes include

phospholipid and cholesterol.

o Method of preparation of liposomes include

active loading technique

and passive loading technique.

o Passive loading techniques include solvent

mechanical dispersion,

solvent dispersion & detergent

solubilisation

o Characterization of liposomes include

physical,chemical and

biological.

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NIOSOMES

INTRODUCTIONNiosomes are non-ionic surfactant based

unilamellar or multilamellar bilayer vesicles

up on hydration of non ionic surfactants

with or without incorporation cholesterol .

The niosomes are very small, and

microscopic in size. Their size lies in the

nanometric scale.

Niosomes are a novel drug delivery system,

in which the medication is encapsulated in a

vesicle. Both hydrophilic

& lipophilic drugs ,entrap either in the

aqueous layer or in vesicular membrane

made of lipid materials.

57

Structure of niosomes:

Head part (hydrophillic)Tail part (hydrophobic)Drug

molecules

Phospholipids

Polar heads facing hydrophilic region

Hydrophobic drugs localized in the hydrophobic lamellae

Hydrophilic drugs located in aqueous regions encapsulated

These vesicular systems are similar to liposomes that can be used as carriers of amphiphilic and lipophilic drugs.

It is less toxic and improves the therapeutic index of drug by restricting its action to target cells.

58

They are osmotically active and stable.

They increase the stability of the entrapped

drug.

The vesicle suspension being water based

offers greater patient compliance over oil

based systems

Since the structure of the niosome offers

place to accommodate hydrophilic, lipophilic

as well as ampiphilic drug moieties, they can

be used for a variety of drugs.

The vesicles can act as a depot to release the

drug slowly and of controlled release.

Biodegradable, non-immunogenic and

biocompatible.

Advantages of niosomes:

59

DISADVANTAGES OF NIOSOMES:

Aggregation

Fusion

Leaking of entrapped drug

Hydrolysis of encapsulated drugs

which limiting the shelf

life of the dispersion.

60

SmallUnilamellarVesicle(SUV)

LargeUnilamellarVesicle(LUV)

MultilamellarVesicle(MLV)

Typical Size Ranges: SLV: 20-50 nm – MLV:100-1000 nm

Classification of niosomes

61

Cholesterol and Non ionic surfactants are the two major components used for the preparation of niosomes.Cholesterol provides rigidity and proper shape. The surfactants play a major role in the formation of niosomes.non-ionic surfactants like spans(span 20,40,60,85,80), tweens (tween 20,40,60,80) are generally used for the preparation ofNiosomes. Few other surfactants that are reported to form niosomes are as follows : Ether linked surfactant Di-alkyl chain surfactant Ester linked Sorbitan Esters Poly-sorbates

Components of niosomes:

62

Factors Affecting Niosomes Formation

Factors affecting niosomes formation

Non-ionic surfactant

nature

Membrane additives

Nature of encapsulated

drug

Surfactants and lipid

levels

Hydration Temperature

alkyl group chain length : C12-C18

Span surfactants with HLB values 4 and 8

Cholesterol: Prevent vesicle aggregation.Dicetyl phosphate: -ve charge

surfactant/lipid ratio: 10-30 mM

Shud be above the gel to liquid phase transition temperature of the system

63

Prediction of vesicle forming ability is not a simply a matter of HLB

CPP = v/lca0

where v - hydrophobic group volume, lc - critical hydrophobic group length and a0 - area of the hydrophilic head group

CPP between 0.5 and 1 likely to form vesicles.

< 0.5 (indicating a large contribution from the hydrophilic head group area) is said to give spherical micelles.

>1 (indicating a large contribution from the hydrophobic group volume) should produce inverted micelles.

Concept of Critical Packing Parameter

64

Sl. No.

Liposomes Niosomes

1. Vesicles made up of concentric bilayer of phospholipids

Vesicles made up of surfactants with or without incorporation of cholesterol.

2. Size ranges from 10-3000nm Size ranges from 10-100nm

3. Comparatively expensive Inexpensive

4. Special storage condition are required

No such special requirement

5. Phospholipids used are unstable Non-ionic surfactants are stable

6. Comparatively more toxic Less toxic

Comparisition between liposomes & niosomes:

65

Hand Shaking method

Reverse phase evaporation technique

Ether Injection method

Multiple membrane

extrusion method

Bubble method

Sonication

From Proniosomes

Methods of Niosome preparation:

66

Hand shaking method:

Surfactant & cholesterol

(150µmole) solution is

dissloved in 10ml ether in

round bottom flask

Rotary evaporator

Ether is evaporated under

vacuum at room

temperature

hydration

Surfactant swells and

peeled off into a film like

lipids

swollen amphiphiles fold to

form vesicles.

Rotary evaporator

67

Reverse phase evaporation technique : Surfactant is dissolved in chloroform ond 0.25

volume of PBS buffer is emulsified to get a W/O emulsion. sonicated chloroform is evaporated under reduced pressure.

The lipid or surfactant forms a gel first and hydrates to form vesicles.

Free drug (unentrapped) is generally removed by dialysis.

sonication:Surfactant +cholesterol mixture is

dispersed in 2 ml aqueous phase in

vial

Mixture is sonicated for 3

min at 60°C using titanium probe

sonicatorUnilamellar niosomes 68

Ether injection Method:Surfactant : cholesterol (150µmole) solution is dissloved in ether

Slowly injected into preheated 4.0ml aqueous phase maintained at 60 c through a 14 gauge needle

Vaporization of ether leads to formation of single layered vesicles.

formation of a bilayer sheet, which eventually folds on itself to form sealed unilamellar vesicles.

14 guage needle

69

Multiple membrane extrusion Method: •Mixture of surfactant,

cholesterol and dicetyl phosphate in chloroform is made into thin film by evaporation

•The film is hydrated with aqueous drug solution and the resultant suspension extruded through polycarbonate membranes

70

Bubble method:RBF as bubbling unit with three necks in water bath.

Reflux , thermometer and nitrogen supply by three

necks

Cholesterol+ Surfactant dispersed in buffer pH 7.4

at 70°C

Above dispersion is homogenized for 15 sec and then bubbled with nitrogen gas at 70°C to get niosomes

It is novel

technique for the

one step

preparation of

liposomes and

niosomes without

the use of

organic solvents. 71

proniosomes:

• Bubble Method• Formation of niosomes from

proniosomes:It is prepared by coating water-soluble carrier such as sorbitol with surfactant. The result of the coating process is a dry formulation. In which each water-soluble particle is covered with a thin film of dry surfactant. This preparation is termed “Proniosomes”.

72

Separation of

unentrapped drug

Dialysis

CentrifugationGel filtration

Separation of unentrapped drug:

Dialyzed in a dialysis tubing against phosphate buffer or normal saline

The unentrapped drug is removed by gel filtration of niosomal dispersion through a Sephadex-G-50 column and elution with phosphate buffered saline

The niosomal suspension is centrifuged and the supernatant is separated. The pellet is washed and then resuspended to obtain a niosomal suspension free from unentrapped drug.

CentrifuserGel Filtration 73

Characterization of Niosomesa) Size, Shape and MorphologyFreeze Fracture Electron Microscopy:- Visualize the vesicular structure of surfactant based vesicles. Photon Correlation spectroscopy :- Determine mean diameter of the vesicles.Electron Microscopy :- Morphological studies of vesicles.b) Entrapment efficiency After preparing niosomal dispersion, unentrapped drug is separated by dialysis and the drug remained entrapped in niosomes is determined by complete vesicle disruption using 50% n-propanol or 0.1% Triton X-100 and analysing the resultant solution by appropriate assay method for the drug. c) Vesicle Suface ChargeDetermined by measurement of electrophoretic mobility and expressed in expressed in terms of zeta potential d) In vitro studies

74

Applications of Niosomes

Applications

Leishmaniasis

Oncology

immunological

adjuvants

Oral drug delivery

Transderm

al

Diagnosti

c imagi

ng

75

MARKETED PRODUCT:Lancôme has come out with a variety of anti-ageing products which are based on noisome formulations. L’Oreal is also conducting research on anti-ageing cosmetic products.

76

Summary :

Niosomes provide incorporating the drug into for a better targeting of the drug at appropriate tissue destination .

  They presents a structure similar to liposome and hence they can represent alternative vesicular systems with respect to liposomes

Niosomes are thoughts to be better candidates drug delivery as compared to liposomes due to various factors like cost, stability etc. Various type of drug deliveries can be possible using niosomes like targeting, ophthalmic, topical, parenteral etc. 

77

REFERENCES:1. S.P. Vyas And R.K. Khar,targeted &

Controlled Drug Delivery,liposomes,173-279.

2. Mohammad Riaz, Liposomes :Preparation Methods, Pakistan Journal Of Pharmaceutical Sciences, January 1996,Vol.19(1),65-77.3. Sharma Vijay K1*, Liposomes: Present Prospective and Future Challenges,International Journal Of Current Pharmaceutical Review And Research, oct 2010,vol1, issue 2,6-164. Himanshu Anwekar*, Liposome- as drug carriers, International Journal Of Pharmacy & Life Sciences, Vol.2, Issue 7: July: 2011, 945-951

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5. Madhav Nvs* And Saini A, Niosomes: A Novel Drug Delivery System, International Journal Of Research In Pharmacy And Chemistry, 2011, 1(3),498-511.6. Lohumi Ashutosh, Rawat Suman, A Novel Drug Delivery System: Niosomes Review, Journal Of Drug Delivery & Therapeutics; 2012, 2(5), 129-135.7. Pawar Sd *, Pawar Rg, Niosome: An Unique Drug Delivery System, International journal Of Pharmacy, Biology and Allied Sciences, April, 2012, 1(3): 406-416.8. Rajesh Z. Mujoriya, Niosomal Drug Delivery System – A Review, International Journal Of Applied Pharmaceutics, Vol 3, Issue 3, 2011,7-10.

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Success in life mostly depends on the power of ‘CONCENTRATION’ --- Swami Vivekananda