COLLOIDAL DISPERSION PHYSICAL PHARMACEUTICS 2

                                             COLLOIDAL DISPERSION

Dispersion medium – A dispersion system is define as a system during which dispersed particles is distributed uniformly thought-out dispersing phase .

Colloidal dispersion- System during which dispersed particles size range 1nm to 1um is distributed uniformly thought out the dispersing phase are called as colloidal dispersion.

Pharmacygyan by Nitesh Vishwkarma

                                              Classification of colloidal dispersion

S.N.	DISPERSION MEDIUM	DISPERSED PHASE	EXAMPLES
1	GAS	LIQUID	FOG
2	GAS	SOLID	SMOKE
3	LIQUID	GAS	FOAM(ARESOAL)
4	LIQUID	SOLID	COLLOIDAL GOLD IN WATER
5	LIQUID	LIQUID	OIL GLOBULES OR WATER GLOBULES
6	SOLID	GAS	SOLID FOAM
7	SOLID	LIQUID	MINIRAL OIL IN WATER
8	SOLID	SOLID	COLLOIDAL GOLD IN GLASS

          Colloidal dispersion are classified into following types

1- Lyophillic colloid

2- Lyophobic colloid

3- Association colloid

Lyophillic colloid :-

* Lyo means solvent.

*Lyophillic colloids are solvent loving colloids.

*Hydrophilic and lipophilic type

* Hydrophilic colloids- includes gelation or acacia which form colloidal dispersion in water.

* Lipophilic colloids- include rubber for Polystyrene whic form colloidal dispersion in organic             solvent. example benzene

*they are thermodynamically stable.

 *viscosity increase with adding dispersed particles .

Lyophobic colloid

 *They are organic and aquas solvent hating colloids.

*When dispersing phase is water they're k/as hydrophobic colloids.

* Colloidal Dispersion of gold or silver in water.

*They are thermodynamically an stable

*Viscosity doesn't increase and adding dispersion phase.

Association collide

*They also are k/as amphilic colloids.

*Few molecules or Ion have both polar and nonpolar Groups.

*There exist separately and Associate at critical micelle and concentration to make micelle of collide size.

*Viscosity increase by adding ampliphile.

Properties of Colloids

                                    Optical properties of colloids are as follows

1. Ultra microscopy

2. Electronic microscopy

3. Light scattering

4. Tyndall effect

Ultra microscopy- 

*When a cell containg colloidal dispersion is viewed through a utltra microscopy against dark background.

*The partical appear as bright spart against dark background.

Electron microscopy- 

*The microscopy is use full in getting picture of a actual particle.

*It helps in studying size, shape, and structure of colloidal particles.

Light scattering –

*When a beam of sunshine is skilled a colloidal dispersion.

*Some light absorbend, some is cattered and remainders is transmuted.

*Absorbed light is liable for calaered nature.

*Scattered light caused the colloidal dispersion to seem Teubidity.

Tyndall effect –

*When a narrow beam of sunshine is skilled a colloidal dispersion.

*The path of sunshine become illuminated.

*This are often abserbed at right angel under ultra microscopy.

*Lyophobic system show I tence tydall effect them lyophollic system.