Md. Istiqur Rahman.
5th Batch, Section: A.
A surface active
agent (surfactant) is a substance
which lowers the surface tension
of the medium in which it is
dissolved, and/or the interfacial
tension with other phases.
The term surfactant is also
applied correctly to sparingly
soluble substances, which lower
Soap, a salt of a fatty acid
(saturated or unsaturated), is a
surface active agent.
A detergent is a surfactant (or a
mixture containing one or more
surfactants) having cleaning
properties in dilute solution.
An emulsifier is a surfactant which
when present in small amounts
A foaming agent is a surfactant
which when present in small
amounts facilitates the formation
Surfactants may act
as detergents, wetting
agents, emulsifiers, foaming
agents and dispersants.
1. Non Ionic SAA
2. Ionic SAA
Non Ionic SAA
I. Simple esters
II. Polyoxyethylene (POE)
III. Sorbitan & mannitan
c) Alkanoates & Carboxylates
a) Heterocyclic compounds
b) Quarternary ammonium salt
Alkanoates & Carboxylates
(i) Cations of strong metallic base
(ii) Cations of weak metallic base
(iii) Cations of weak organic base
Surfactants are usually organic
are amphiphilic, meaning they
contain both hydrophobic groups
(their tails) and hydrophilic groups
A surfactant contains both a water
insoluble (or oil soluble)
component and a water soluble
Surfactants will diffuse in water
and adsorb at interfaces between
air and water or at the interface
between oil and water, in the case
where water is mixed with oil.
The insoluble hydrophobic group
may extend out of the bulk water
phase, into the air or into the oil
phase, while the water soluble
This alignment of surfactants at
the surface modifies the surface
properties of water at the water/air
or water/oil interface.
Sodium stearate, the most
common component of most
soap, which comprise about 50%
of commercial surfactants.
Pharmaceutical Use of
SAA used in emulsions as an emulsifying agent.
SAA used in suspensions as a flocculating
SAA as a wetting agent.
SAA as a bactericidal agent.
SAA as a solubilizing agent.
To modify the properties of membranes.
Enhancement of percutaneous absorption.
Enhancement of transport across mucosal
membranes (rectal, vaginal, ophthalmic, nasal).
SAA as a foaming agent.