micro spheres

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-:Contents of Seminar :-

Introduction

Advantage

Polymar used for preparation

General Method of Preparation

Characterization of Microspheres.

Application of Microspheres2Visit www.bpharmstuf.com

-: Introduction :-

• Microspheres are solid , approximately spherical

particles ranging 1-1000µm in size.

• They are made up of polymeric substance in which

the drug is dispersed through out the microspheres

matrix.


ADVANTAGE OF MICROSPHERES: They facilitate accurate delivery of small quantities of potent drug and

reduced concentration of drug at site other than the target organ or tissue.

They provide protection for unstable drug before and after

administration, prior to their availability at the site of action.

They provide the ability to manipulate the in vivo action of the drug,

pharmacokinetic profile, tissue distribution and cellular interaction of the

drug.

They enable controlled release of drug.

Ex: narcotic, antagonist, steroid hormones


POLYMER Used for Microspheres preparation:


The administration parameters that can be satisfactorily controlled are as follow:

• Taste and odour masking

• Conversion of oil and other liquids, facilitating ease of handling

• Protaction of the drug from the environment

• Delay of volatillisation

• Freedom from incompatibilities between drug and

excipients,especially the buffers

• Improvement of flow properties

• Safe handling of test masking

• Dispersion of water insoluble substance in aqueous media

• Production of sustained release, controlled release and targeted

medication


General Method of Preparation:

a) Single Emulsion Technique

b) Double Emulsion Technique

c) Polymerization Technique

d) Phase Separation Coacervation

e) Spray drying &spray coating

f) Solvent Extraction8Visit www.bpharmstuf.com

A) Single Emulsion Technique Aqous solution /suspension of polymer(natural polymer)

stirring / sonication

dispersion in orgenic phase oil/chcl3

cross linking

Heat denaturation chemical crosslinking

(by adding dispersion (butanol,HCHO,Glutaraldehyde)

To heated oil)

Aqous solution /suspension of polymer(natural polymer)

stirring / sonication

dispersion in orgenic phase oil/chcl3

cross linking

Heat denaturation chemical crosslinking

(by adding dispersion (butanol,HCHO,Glutaraldehyde)

To heated oil)


Microspheres in org.phase Microspheres in org.phase

Centrifugation,washing,separation

Microspheres

Microspheres in org.phase Microspheres in org.phase

Centrifugation,washing,separation

Microspheres


Single Emulsion Technique


B) Double Emulsion Technique

Aqueous solution of polymer

dispersion in oil/orgenic phase, vigorous homogenisation(sonication)

Primary emulsion(w/o)

addition of aqueous solution of PVA

W/O/W multipal emulsion

addition of large aq. Phase

MICROSPHERES in solution

Aqueous solution of polymer

dispersion in oil/orgenic phase, vigorous homogenisation(sonication)

Primary emulsion(w/o)

addition of aqueous solution of PVA

W/O/W multipal emulsion

addition of large aq. Phase

MICROSPHERES in solution


Separation,washing, drying

MICROSPHERES

Separation,washing, drying

MICROSPHERES


C)Polymerization

A)Normal Polymerization:Normal Polymerization is done by bulk, suspension, pption,emulsion and

polymerization process.

1.Bulk polymerization: Monomer Bioactive material Initiator Heated to initiate polymerization Initiator accelerate rate of raction

Polymer(Block) Moulded/fragmented

MICROSPHERES

A)Normal Polymerization:Normal Polymerization is done by bulk, suspension, pption,emulsion and

polymerization process.

1.Bulk polymerization: Monomer Bioactive material Initiator Heated to initiate polymerization Initiator accelerate rate of raction

Polymer(Block) Moulded/fragmented

MICROSPHERES14Visit www.bpharmstuf.com

B)Suspension polymerization

Monomer Bioactive material Initiator

Dispersion in water and stebilizer

Droplet

Vigorous ,Aggitation Polymerization by Heat

Hardened microspheres

Separation&Drying

MICROSP HERES

Monomer Bioactive material Initiator

Dispersion in water and stebilizer

Droplet

Vigorous ,Aggitation Polymerization by Heat


Separation&Drying

MICROSP HERES


3) Emulsion PolymerisationMonomer/ Aq.Solution of NaOH,

Bioactive material Initiator, Surfactant , Stabilizer

Dispersion with vigorous stirring

Micellar sol. Of Polymer in aqueous medium

Polymarization

Microspheres formation

MICROSPHERES

Monomer/ Aq.Solution of NaOH,

Bioactive material Initiator, Surfactant , Stabilizer

Dispersion with vigorous stirring

Micellar sol. Of Polymer in aqueous medium

Polymarization

Microspheres formation

MICROSPHERES 16Visit www.bpharmstuf.com

D)Phase Sepration CoacervationD)Phase Sepration Coacervation Aq./orgenic solution of polymer

Drug dispersed or dissolved in the polymer solution Phase sepration by salt addition, non solvent addition add. Incompatible polymer,etc Polymer rich globules Hardening microspheres in aqu./orgenic phase sepration/drying MICROSPHERES

Aq./orgenic solution of polymer

Drug dispersed or dissolved in the polymer solution Phase sepration by salt addition, non solvent addition add. Incompatible polymer,etc Polymer rich globules Hardening microspheres in aqu./orgenic phase sepration/drying MICROSPHERES 17Visit www.bpharmstuf.com

Phase Sepration Coacervation


E)Spray DryingE)Spray Drying Polymer dissolve in volatile organic solvent(acetone,dichloromethane)

Drug dispersed in polymer solution under high speed homogenization

Atomized in a stream of hot air

Due to solvent evaporation small droplet or fine mist form

Leads to formation of Microspheres

Microspheres separated from hot air by cyclone separator,Trace of solvent are removed by vacuum drying

Polymer dissolve in volatile organic solvent(acetone,dichloromethane)

Drug dispersed in polymer solution under high speed homogenization

Atomized in a stream of hot air

Due to solvent evaporation small droplet or fine mist form

Leads to formation of Microspheres

Microspheres separated from hot air by cyclone separator,Trace of solvent are removed by vacuum drying 19Visit www.bpharmstuf.com

F)Solvent ExtractionF)Solvent Extraction Drug is dispersed in organic solvent

(water miscible organic solvent such as Isopropanol)

Polymer in organic solvent

Organic phase is removed by extraction with water (This process decreasing hardening time for microspheres)


Drug is dispersed in organic solvent

(water miscible organic solvent such as Isopropanol)

Polymer in organic solvent

Organic phase is removed by extraction with water (This process decreasing hardening time for microspheres)



Solvent extraction apparatusS


Characterization of MicrospheresCharacterization of Microspheres

Partical size & shape

Surface chemistry by Electron Spectroscopy

The Surface chemistry of microspheres can be determine using the

electron spectroscopy for chemical analaysis It provide a mens of

determination of atomic composition of the surface.

Release study

Usually carried out in phosphate saline buffer ph 7.4.

Two method 1) Rotating paddle dissolution apparatus.

2) Dialysis method 22Visit www.bpharmstuf.com

Iso electric point

Microelectrophoresis apparatus is used to measure

elecrophoretic mobility of microspheres from which

isoelectric point can be determine.

It can be correlated to surface charge or ion adsorption of

microspheres.

Density Determination

Density measured dy using a multivolume pychometer.


Application of MicrospheresApplication of Microspheres

Microspheres in Vaccine delivery

Targeting of Drug

Magnetic Microspheres

Immunomicrospheres

Microsponges: Topical Porous Microspheres

Imaging

Surface modifide Microspheres 24Visit www.bpharmstuf.com

REFERENCES

• http://www.daviddarling.info/encyclopedia/M/microsphere.html

• www.rsc.org/chemistryworld/News/2010/.../22071001.asp

• www.physorg.com/news187971041.htm• REZA ARSHADY- MICROSPHERES

MICROCAPSULES &LIPOSOMES


http://www.daviddarling.info/encyclopedia/M/microsphere.html

http://www.daviddarling.info/encyclopedia/M/microsphere.html

http://www.physorg.com/news187971041.htm

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