MUDASIR MALIK

2. Colloids and their role in
Pharmaceutical Industry

3. Colloids
A mixture in which very small particles of one substance are
distributed evenly throughout another substance.

4. History
 This term was first used in 1862 to
to distinguish colloids from
crystalloids.
Colloids have been studied by
scientists since the early 1800’s.

5. Introduction
 The word “colloid” was derived from the Greek, “kolla” for
glue.
 Colloid is short synonym for colloidal system.
 The heterogeneous biphasic system.
 Size of colloidal particle ranges from 1nm to 100nm.

6. Classification
There are two criteria's for classification of
colloids.
1. Based on the state of Aggregation of phase
2. Based on the interaction of phase

7. Aggregation of phase
Based on the state of aggregation of
dispersed phase and dispersion medium,
colloidal solutions are classified into
1. Aerosol (liquid or solid in gas)
2. Foam (gas in liquid)
3. Emulsion (liquid in liquid)
4. Sol (solid in liquid)
5. Gel (liquid in solid)

8. Interaction of phase
On the basis of affinity between two phases,
colloidal solutions are classified into
1. Lyophobic sols
Examples sols of
Metals, sulphur
2. Lyophilic sols
Examples gums, starch

9. Preparation
Two methods are generally used for the
preparation of colloidal solutions.
1. By Condensation
2. By Dispersion

10. General Properties
1. Phase Heterogeneous
2. Particle size 1nm to 100nm
3. Separation Ultrafiltration
4. Setting Settles on centrifugation
5. Appearance Generally clear
6. Diffusion Diffuse slowly
7. Color Invariably colored
Examples Milk, Blood, fog

11. Kinetic properties
Brownian motion
Rapid, random, zigzag movement of colloidal
particles through dispersion medium.
This movement is due to bombardment of
colloidal particles by the molecules of
dispersion medium.

12. Optical properties
Tyndall Effect
Light scattering by colloidal particles.
Bright cone of scattered light is called Tyndall
cone.

13. Electrical properties
Charges on colloidal particles:
Colloidal particles always
carry some charge otherwise
the colloidal solution would
be unstable.
It may be positively or
negatively charged.
Due to acidic and basic groups

14. Purification
The colloidal solutions prepared by any
method contain different impurities.
They can be separated by
1. Dialysis
2. Ultrafiltration

15. Role in pharmaceutics
Therapy
Colloidal system are used as therapeutic
agents in different areas.
Colloidal medicines are more effective and are
easily absorbed in our system.
Example ,penicillin and streptomycin.

16. Eye lotions
There are various eye lotions that are
prepared by colloidal solutions.
Argyrol and protargyrol

17. Colloidal sulphur
It is used as disinfectants.
It is a homeopathic
remedy used to treat
skin conditions such as
psoriasis, eczema etc.

18. Colloidal copper
It is used in treatment of
cancer.
It is used as a remedy for
burns, arthritis, parasites,
viral and bacterial infections.

19. Colloidal Gold
It is diagnostic agent for paresis.
It is used as mineral
supplement to augment
the body’s immune system.

20. Colloidal Mercury
 It is used in treatment of syphilis.

21. Colloidal silver
It is an unrivalled anti-biotic.
It destroy all types of virus, bad fungi and
bacteria.
It promotes healing.

22. Colloidal electrolytes
Increase solubility, stability and taste of
compounds
Used as additives in drugs
E.g. Quaternary Ammonium salts

23. colloidal Silica
Prevents flocculation.
Stability to drugs.
e.g. silicon dioxide

24. Natural colloids
Plasma protein.
Gelatin coating over tablets and granules.
For protection.

26. Conclusion
A knowledge of colloid chemistry is essential
to understand some of the various natural
phenomena around us.
Colloids make up some of our modern
products.
It has some disadvantages because of metals
used but its normal level is safe.