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Colloidal dispersion system
- 1. Colloidal Dispersion System AssistantProfessor Miss. Priya P. Mane Deshmukh College of Pharmacy , Paniv
- 2. Disperse particles consistof: Internal Phase/ Dispersed Phase Dispersed Medium
- 3. Colloidal system isdispersion where in internal phase dispersed particles are distributed uniformly in a dispersion medium (External/continuous Phase). Particle size-0.5 to 1 micron In colloidal systems particles pass through filter paper but do not pass through semi permeable membrane diffuse very slowly. Exemples:-Liposome, Nanoparticles, Paint, Milk,Radioactive Colloids-198Au,98mTc Colloidal system
- 4. Class Particle Size*Characteristics of System Examples Molecular dispersion Lessthan 1nm Invisible in electron microscope Passthrough ultrafilter and semipermeable membrane Undergo rapid diffusion Oxygen molecules, ordinary ions, glucose Colloidal dispersion From 1nm to 0.5 µm Not resolved by ordinary Colloidal silver sols, microscope (although natural and synthetic may be detected under polymers, cheese, butter, ultramicroscope) jelly, paint, milk, shaving Visible in electron cream, etc. microscope Passthrough filter paper Do not pass semipermeable membrane Diffuse very slowly Coarse dispersion Greater than 0.5µm Visible under microscope Grains of sand, most Do not pass through pharmaceutical emulsions normal filter paper and suspensions, red blood Do not dialyze through cells semipermeable membrane Do not diffuse * 1 nm (nanometer) = 10-9 m; 1 µm (micrometer) = 10-6 m. CHAPTER 05 Classification of dispersion Colloidal system
- 5. Coarse Dispersio (Exp: Fatemulsio Molecular Dispersion (Exp:Glucose Solution) Colloidal Dispersion (Exp: Gold ColloidalDispersion)
- 6. Dispersed Phase Dispersion Medium Colloid Type Examples SolidSolid Solid sol Pearls, opals Liquid Solid Solid emulsion Cheese, butter Gas Solid Solid foam Pumice, marshmallow, sponge Solid Liquid Sol, gel Jelly, paint, blood Liquid Liquid Emulsion Milk, mayonnaise Gas Liquid Foam Whipped cream, shaving cream Solid Gas Solid aerosol Smoke, dust Liquid Gas Liquid aerosols Clouds, fog Gas Gas --- None (A gas in a gasalways produces a solution) Classification of Colloidal I.The original states of their component parts
- 7. II. Colloidal solutionscan be classified in different ways:- A. Based upon molecular size:- 1.Macromolecular colloids 2. Multi molecular colloids 3. Associated colloids B. Based upon interaction among phases:- 1. lyophilic colloids 2.lyophobic colloids 3.Amphiphilic colloids
- 8. Lyophilic (Solvent-loving) Colloids Systems containingcolloidal particles that readily interact with the dispersion medium Due to their affinity for the dispersion medium, such materials can easily form colloidal dispersions; simply by dissolving the material in the solvent being used. Most lyophilic colloids are organic molecules, for example, gelatin, acacia, insulin, albumin, rubber, and polystyrene. Lyophobic (Solvent-hating) Colloids Systems composed of materials that have little attraction, if any, for the dispersion medium It is necessary to use special methods to prepare lyophobic colloids. They are generally composed of inorganic particles dispersed in water. Examples of such materials are gold, silver, sulfur, arsenous sulfide, and silver iodide. Amphiphilic Colloids Systems composed of amphiphiles or surface-active agents, that are characterized by having two distinct regions of opposing solution affinities within the same molecule or ion. When present in a liquid medium at low concentrations (below the CMC), the amphiphiles exist separately and are of subcolloidal size As the concentration is increased (above the CMC), micelles are formed which may contain 50 or more monomers, the diameter of each micelle is of 5 nm (colloidal size). The formation of amphiphilic colloids is spontaneous, if the concentration of the amphiphile exceeds the CMC
- 9. Colloidal Dispersion Properties 1.OpticalProperties • Farraday Tyndall Effect • Electron Microscopy Imaging • Light ScatteringOptical Properties 2.Kinetic Properties 1. Brownian motion 2. Sedimentation 3. Viscosity 4. Diffusion 3. Electrical Properties • Electrical double layer • Electrophoresis • Electrosmosis • Donnan membrane effect
- 10. Optical Properties ofColloidal Dispersion Turbidity Tyndall Faraday Effect
- 11. Brownian Motion (Kinetic Propertyof Colloids) Viscosity η = ηo (1+ 2.5 φ) Diffusion Stokes Einstein Equation Osmotic Pressure Van Hoff Equation Sedimentation Stokes’s Law
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- 17. Application s ofcolloids 1. Stability 2. Diagnostic agents 3. Toxicity 4. Absorption 5. Targeted drug delivery 6. Therapeutic effects 7. Parenteral