RANJEET Nanodipers Systems

8/3/2019 RANJEET Nanodipers Systems

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PRESENTED BY:-

RANJEEET KUMAR

M. Pharm 1st sem(pharmaceutics)

Department of pharmaceutical sciences

Dibrugarh University


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NANODISPERSED SYSTEMS

Nanodispersed system is dispersion of nano-

particles which contains :

y Membrane forming molecules

y A lipophilic component

y A coemulsifier


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TYPES OF NANODISPERSED SYSTEMS

y Liposome: Lipid bilayer enclosing an aqueous core


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y Nanoemulsion: Lipid monolayer enclosing a liquidlipid core


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y Lipid nanoparticle: Lipid monolayer enclosing asolid lipid core


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LIPOSOMES

y Liposomes are simple microscopic vesicles in which anaqueous volume is entirely enclosed by a membrane composed

of a lipid molecule.

y The lipids are predominantly phospholipids which formbilayers similar to those found in bio-membranes

y In most cases the major component is phosphatidyl choline.It contrast markedly with other amphipathic molecules such asdetergent & lysolecethin they formed bi-layer sheets notmicellar structure.

y This is thought to be because the double fatty acid chain givesthe molecule tubular shape- more suitable for aggregation inplanar sheets compared with detergents with polar head andsingle chain whose conical shaped fits nicely into the sphericalmicellar structure.


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Chemical structure and schematic representation of a

phospholipid (lecithin)

A hydrophilicpolar head

group

A pair of

hydrophobicacyl

hydrocarbonchain


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Schematic illustration of liposomes of different size and

number of lamellae

SUV: Small unilamellar vesicles, LUV: Large unilamellar vesicles,MLV: Multilamellar vesicles, MVV: Multivesicular vesicles

The thickness of the membrane (phospholipid bilayer) measures

approximately 5 to 6 nm.

20-100 nm

> 100 nm

>0

.5 m > 1 m


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COMMON STAGES FOR THE METHOD OF PREPARATION

LIPOSOMES

Cholesterol LecithinC

harge

Dissolve in organic solvent

Solution in organic solvent

Drying

Thin flim

Dispersion hydration

Liposome suspension


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APPLICATIONy LIPOSOMES AS DRUG CARRIERS

The application of liposome as a drug-delivery systemhas become more popular over the last decades,

because of their biocompatibility and versatility incarrying systemically administered drugs such aschemotherapeutics and antibiotics with narrowtherapeutic windows their systemic circulation time

reduce toxicity by lowering plasma free drugconcentration and facilitate preferential localization ofdrugs in solid tumours based on increased endothelialpermeability and reduced lymphatic drainage orenhanced Permeability.


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NANOEMULSIONSy Nanoemulsions can be defined as oil-in-water

emulsions with mean droplet diameters ranging

from 50 to 1000 nm.

y Usually, the average droplet size is between 100and 500 nm.

y The terms sub-micron emulsion (SME) and mini-emulsion are used as synonyms.


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TYPES OF NANOEMULSION

y Three types of Nanoemulsions are most likely to beformed depending on the composition:

y Oil in water Nanoemulsions wherein oil droplets aredispersed in the continuos aqueous phase

y Water in oil Nanoemulsions wherein water droplets aredispersed in the continuous oil phase;

y Bi-continuous Nanoemulsions wherein microdomainsof oil and water are interdispersed within the system.

y In all three types of Nanoemulsions, the interface isstabilized by an appropriate combination of surfactantsand/or co-surfactants.


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PREPARATION OF NANOEMULSION

y The drug is to be dissolved in the lipophilic part of theNanoemulsion i.e. oil and the water phases can be

combined with surfactant and a co-surfactant is thenadded at slow rate with gradual stirring until thesystem is transparent. Ultrasonicator can finally beused so to achieve the desired size range for dispersedglobules. It is then being allowed to equilibrate.


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NANOEMULSIONS-LIPOSOMESy Nanoemulsions therefore differ clearly from the liposomes,

where a phospholipid bilayer separates in an aqueous core from

a hydrophilic external phasey If nanoemulsions are prepared with an excess of phospholipids,

liposomes may occur concurrently

y Due to their lipophilic interior, nanoemulsions are more

suitable for the transport of lipophilic compounds thanliposomes.

y Similar to liposomes, they support the skin penetration ofactive ingredients and thus increase their concentration in the

skin


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LIPID NANOPARTICLESy Lipid nanoparticles have a similar structure as

nanoemulsions.

y Their size ranges typically from 50 to 1000 nm.

y

The difference is that the lipid core is in the solid statey The matrix consists of solid lipids or mixtures of lipids.


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Scheme for the production of lipid nanoparticles by the hot or cold homogenization

technique

1 Melt lipid; dissolve or solubilize active ingredient in the lipid

. Hot homogenization technique Cold homogenization technique

2 Disperse melted lipid in hot aqueous surfactant

solution

Cooling and recrystallization of active lipid mixture using

liquid nitrogen or dry ice

3 Preparation of a pre-emulsion by means of a rotor-

stator homogenizer

Milling of the active lipid mixture by means of a ball mill or

a jet mill

4 High-pressure homogenization above the melting

point of the lipid

Disperse lipid microparticles in cold aqueous surfactant

solution

5 Cooling and recrystallization High-pressur homogenization at or below room

temperature


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SLN

y Three diiferent models for incorporation of activeingredients into SLN

Homogeneous matrix model

Drug-enriched shell modelDrug-enriched core model


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SLN

y A homogeneous matrix with molecularly dispersed drug

or drug being present in amorphous clusters is thought tobe mainly obtained when applying the cold

homogenisation method and when incorporating very

lipophilic drugs

y An outer shell enriched with active compound can beobtained when phase separation occurs during cooling

process from the liquid oil droplet to the formation of a

solid lipid nanoparticle


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SLN

y A core enriched with active compound can be when the

opposite occurs, which means the active compound startsprecipitating first and the the shell will have distinctly less

drug

y This leads to a membrane controlled release governed by

the Fick law of diffusion.


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SLN : Advantagesy Possibility of controlled drug release and drug targeting.y Increased drug stability.

y High drug payload.

y Incorporation of lipophilic and hydrophilic drugs

fesibility.y No biotoxicity of the carrier.

y Avoidance of organic solvents.

y No problems with respect to large scale production andsterilization

y A potential advantage of this nanoparticle adhesiononto the skin is that there would be a possible depotformation mechanism .


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References

y Target & controlled drug delivery-N0vel carriersystems by S.P.Vyas & R.K.Khar page no-155-189

yControlled and novel drug delivery systems, chapter-15, liposome as drug carrier by Sanjay K. Jain & N.KJain -168-201

y Shinoda K, Lindman B; Organised surfactant systems:

micro-emulsions, Langmuir 1987; 3, 135149.y Controlled Drug Delivery: Fundamentals and

Applications, Second Edition, Revised and Expanded,edited by Joseph R. Robinson and Vincent H. Jee. page

no -210

-256


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THANK YOU

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RANJEET Nanodipers Systems

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