Seminar on : Seminar on MICROSPHERES
M.Pharm(P’Ceutics) -:Contents of Seminar :- : -:Contents of Seminar :- Introduction
Polymar used for preparation
General Method of Preparation
Characterization of Microspheres.
Application of Microspheres -: Introduction :- : -: 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: : 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: : POLYMER Used for Microspheres preparation: The administration parameters that can be satisfactorily controlled are as follow: : 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: : 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 Extraction A) Single Emulsion Technique : A) Single Emulsion Technique Aqous solution /suspension of polymer(natural polymer)
stirring / sonication
dispersion in orgenic phase oil/chcl3
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 B) Double Emulsion Technique : B) Double Emulsion Technique Aqueous solution of polymer
dispersion in oil/orgenic phase, vigorous homogenisation(sonication)
addition of aqueous solution of PVA
W/O/W multipal emulsion
addition of large aq. Phase
MICROSPHERES in solution Separation,washing, dryingMICROSPHERES : Separation,washing, dryingMICROSPHERES C)Polymerization : C)Polymerization A)Normal Polymerization:
Normal Polymerization is done by bulk, suspension, pption,emulsion and polymerization process.
Monomer Bioactive material Initiator
Heated to initiate polymerization
Initiator accelerate rate of raction
MICROSPHERES B)Suspension polymerization : B)Suspension polymerization Monomer Bioactive material Initiator
Dispersion in water and stebilizer
Vigorous ,Aggitation Polymerization by Heat
MICROSP HERES 3) Emulsion Polymerisation : 3) Emulsion Polymerisation Monomer/ Aq.Solution of NaOH,
Bioactive material Initiator, Surfactant , Stabilizer
Dispersion with vigorous stirring
Micellar sol. Of Polymer in aqueous medium
MICROSPHERES D)Phase Sepration Coacervation : D)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
microspheres in aqu./orgenic phase
MICROSPHERES E)Spray Drying : E)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 F)Solvent Extraction : F)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)
Hardened microspheres Characterization of Microspheres : Characterization 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.
Usually carried out in phosphate saline buffer ph 7.4.
Two method 1) Rotating paddle dissolution apparatus.
2) Dialysis method Slide 20: 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 measured dy using a multivolume pychometer. Application of Microspheres : Application of Microspheres Microspheres in Vaccine delivery
Targeting of Drug
Microsponges: Topical Porous Microspheres
Surface modifide Microspheres Slide 22: THANK YOU