Colloidal dispersion and use in pharmacy.

1. Topic:Colloidal Dispersion
Presentaion By:
Ms.Bhagwat S.S.
M.Pharm
Pharmaceutics

2. • 1.Optical Properties
• 2 Kinetic Properties
• 3 Electrical Properties

3. Tynadl Effect
Ultramicroscope
Electron Microscope
Light scaterring effect

4. Brownian motion
Diffusion
Osmotic pressure
Sedimentation
Viscosity

5. • In normal dispersion ,the disperse phase or particle tends to get
setttle down under the influence of gravity,but in case of
colloidal dispeison the brownian movement tends to offset
sedimentaion ,but promote the mixing.
• Stroger force rquire to brings about sedimentation.
• Ultracentrifugation is generally used for bringing baout and
studing a sedimentation in colloidal dispersion.
• In Ultracentifugation particle are settle down according to their
molecular weight and hence helpful in determing molecular
wt.

6. • Elctrical Double layer
• Counter Ion
• Stern Layer
• Gouy chapman Layer-10-100Amstrong

7. Electro-osmosis
• Atmoshere of counter ions confirm the charge on medium Which is
opposite to that of charge particle.
• Hence liquid flow in one direction and particle flow in othet direction
unnder the influence of elctric feild.
• This phenomenon is known as electrosmosis.
• The pressure produce by this proces of elcetro osmosis is known as
elctro osmotic pressure.
• E.g.Glass powder.with electrode immersed in dil.buffer solution on
eighter side of plug.
• Glass surface is i cotact with water ,bears negative charge due to
absorption of OH- of water .
• so as current passes,the liquid will passes toward positive electrode.
• This will obsereved if capillary tube is attach to the end of
tube,displacement of liquid will be visible.

8. Stable System
Floculation Sedimentation
Coagulation Floculation
Sedimentation Coagulation
Phase seperation

9. Stabilization serves to prevent coagulation of
colloids
Mechanisms:
• Steric stabilization
• Electrostatic stabilization

10. • Lyophobic colloids
• Lyophilic colloid
• Assosciation colloids
• Salting out
1.Schulze hardy rule
Depending upon number of charges on ions precipitation
power is increase or decrease.
2.Gold number
mg of hydrophilic collids which when added to 10 ml red
gold sol prevent change in red to violet 1ml 10% NaCl

11. • Four scientist derjaguin ,landu in USSR and Veruvey
,overbeek in netherland in 1940s carry out study of a
qualitative theory of the interaction between lyophobic
disperse particle.
• According to this theory distance between two particle mainly
influence particle -particle intereaction.
• 1.Repulsion forces
• 2.Attraction forces
• Four Case
• Case I:Two particle of Same charge
• Case II:Paticle of Opposite charge
• Case III:Particle of same charge bringing together with force
• Case IV:PArticle of same charge with the addition of small
amound of electrolyte.