Modified Micro Sphere- Saurabh Rawat

8/4/2019 Modified Micro Sphere- Saurabh Rawat

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Saurabh Rawat

M. Pharm. 2ND Sem. (Pharmaceutics)


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Microspheres are solid , approximatelyspherical particles ranging 1-1000m insize.

They are made up of polymericsubstance in which the drug is dispersedthrough out the microspheres matrix.

Modification in this microsphere meanschanging the polymer, changing thedrug release profile, make it morespecific to site of action in the body.


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1. Albumin microspheres

2. Hydrophilic human albumin microsphere

3. PLA/PLGA microspheres4. Magnetic microspheres

5. Immunomicrospheres

6. Microsponges(topical microspheres)

7. Surface modified microspheres

8. Dextran hydrogel microspheres


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PMMA in chloroform

and toluene

HAS in diss. water

mixture

Glutaraldehyde

saturatedtoluene(GST)

Cross linked HAS

microsphere

Hydrophilic human

albumin microsphere


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PLGA in methylene

chloride (1 part)

Drug in methylene

chloride (1 part)

PVA in water

Warm at 65C

PLGA and drug soln in methylene chloride

(organic phase)

Mixing of organic phase with aqueous

phase

Transfer the mixture into the

isopropyl alcohol(5% v/v)

MIX

SONICATE

PVA and glycerol in

water (aqueous phase)

Add glycerol

stirring

Mag. Stirring for 30 min followed by centrifugation


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MMS(magnetic microsphere) are supermolecular small particle.

Circulate through capillaries.

Magnetic microspheres were developedto overcome 2 major problems reticulo-endothelial (RES) clearance and toincrease target site specificity

This is prepare mainly two method namelyPhase separation emulsion polymerization(PSEP) & continuous solvent evaporation(CSE)


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Aq.Sol(albumin

+ drug +

magnetite)

Vegetable

oil

Emulsification

HeatCross -linking

agent

Microsphere

suspension speeratedfrom oil

Dr y and

store at 4oc


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Solution in volatile organic solvent

(polymer+drug+magnetite)

Auxiliary solution

magnetic microspheres seperated bycentrifugation

(freeze drying & store at at 4oc )


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Advantages:

Protect drug, Blood cells.

Deliver up to 60% of drug to the target tissue

Drug available in controlled manner. Reduce concentration of free drug

Minimize damage to normal cells

Disadvantages:

Expensive

It req specialized microspheres & magnets

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IMMUNOMICROSPHERES:

Monoclonal antibodies mediated targeting is amethod used to achieve selective targeting to thespecific site.

Monoclonal antibodies are extremely specific

molecules. Mabs can be directly attached to the

microspheres by means of covalent coupling. The free Aldehyde groups, amino groups or

hydroxyl group on the surface of microspheres canbe linked to antibodies.

The Mabs can be attached to the microspheres byany of the following methods; Non specific adsorption Specific adsorption Direct coupling via reagent

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particle size range 5-300 micro meter. These microsponges having capacity to

entrap wide range of active ingredients. topical carrier system. Use in creams, lotions and powders. Microsponges consists of non collapsible

structures with porous surface.

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Microsponges are prepared by severalmethods utilizing emulsion systems as wellas by suspension polymerization in a

liquid

liquid system.

The most common emulsion system used

is oil-in-water (o/w), with themicrosponges being produced by theemulsion solvent diffusion (ESD) method.


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The organic internal phase containing drugand polymer in dichloromethane.

External phase contained PVA asemulsifying agent & mix.

Internal phase is gradually added intoexternal phase.

Stirred at 1,0002,000 rpm for 3 h at roomtemperature to remove dichloromethanefrom the reaction flask. The formedmicrosponges were filtered, washed withdistilled water,


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The objective of drug therapy using carriers is theselective delivery of drug to specific sites in the

body.

The phagocytosis of colloidal carriers, rapidclearance and passive distribution are common

disadvantages of particulate system. The change in the biophysical behavior of the

particles helps to avoid the difficulties in targeting.

Different approaches have been utilized to change

the surface properties of carriers to protect themagainst distribution pattern.

Protein microspheres covalently modified by PEGderivatives.

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Among the most studied modifiers are:

Antibodies and their fragments.

Proteins

Mono-, oligo-.and polysaccharide.

Chelating compound (EDTA, DTPA orDesferroxamine).

Synthetic soluble polymers.

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Aq. Soln of methylated

dextranAq. Soln of PEG

W/W emulsion of dextran in aq.

Soln of PEG

HYDROGEL MICROSPHERE

Emulsification

Radical Polymerization


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Hydroxyethyl methacrylate(HEMA)

Methacrylic acid(MAA)

Dimethylaminoethyl methacrylate (DMAEMA)


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Jain, N.k.;Advances in controlled and novel drug delivery ;CBS publishers,delhi 2010;1st ed. pp- 177-179

Vyas, s.p.,khar roop k.;controlled drug delivery; vallabh prakashan, delhi2008; 2nd ed. pp- 528-532.

Amrutiya Netal et al.(2009);Development of microsponges for topicaldelivery of mupirocin; AAPS PharmSciTech, Vol. 10, No. 2, June 2009 Zhao Hong et al.(2009); Preparation of biodegradable magnetic

microspheres with poly(lactic acid)-coated magnetite ; Journal ofMagnetism and Magnetic Materials 321 ;pp- 13561363.

Raje Urs, Veera Ashvini et al. (2010); Albumin microspheres: an uniquesystem as drug delivery carriers for non steroidal anti-inflammatory drugs

(NSAIDs); International Journal of Pharmaceutical Sciences Review andResearch, Volume 5, Issue 2, NovemberDecember; pp -10-18 Salim Md. et al.(2009); Magnetic microspheres as a magnetically

targeted drug delivery system; journal of global pharma technology.2010; 2(3):pp- 36-46.

Patel et al.(2011), Microsphere as a novel drug delivery; Int. J. of Pharm.& Life Sci. (IJPLS), Vol. 2, Issue 8: Aug;pp- 992-997.

Deshmukh kirti ,solid porous microsphere: emerging trend inpharmaceutical Technology; International Journal of Pharma and Bio Sciences;vol-2,

issue 1, jan march 2011:pp 364-377. Van Tomme, Sophie R. et al.(2005); Self-gelling hydrogels based on

oppositely charged dextran microspheres; Biomaterials 26 ;pp- 21292135


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Modified Micro Sphere- Saurabh Rawat

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