This document discusses three topics related to surface and interfacial tension: solubilization, detergency, and adsorption at solid interfaces. Solubilization is the process of increasing the solubility of organic compounds in water using surfactants. Detergency is the removal of dirt from surfaces using detergents, which are surfactants. Adsorption at solid interfaces is when substances deposit on the surface of solids, with the deposited substance called the adsorbate and the surface called the adsorbent. Adsorption depends on factors like the nature of the adsorbent and adsorbate, temperature, and can be physical or chemical in nature.

1. IIIrd Semesester B. pharmacy
Physical Pharmaceutics-I
Unit-III
Surface and Interfacial tension [Part-6]
( Solubilization, Detergency, Adsorption at solid interface )
Miss. Pooja D. Bhandare
(Assistant professor)
Kandhar college of pharmacy

2. Solubilization
• It is the process in which, solubility of organic compound is increased
in aqueous medium with the help of surface active agents (surfactant),
this phenomenon is know as solubilization.
• It is used in many industries for the mixing of two immiscible liquids
and help in making of drug.

3. Detergency
• It is the process or phenomenon in which dirt ( aid and solid object)
remove from the surface with the help of detergent.
• Find these detergent are basically made up with surfactant or itself
surfactant.
• It whole that, it reduce the adhesive force, so dirt particle easily
remove from the surface.

4. Adsorption at solid interface
• When substance (material) deposit on the surface of solid is called the
adsorption at solid interface.
• Thus material (substance) which deposit on the surface of solid is
called adsorbate.
• The material (substance) on whose surface the process take place is
called adsorbent.

5. • Adsorption of a gas or a liquid onto a solid surface is important in
pharmacy.
• The degree of adsorption of gas by a solid depends on the
1. Nature od adsorbent and its surface area
2. Nature of adsorbate and the partial pressure of gas
3. Temperature

6. • Depending on the nature of interaction, adsorption is classified into
physisorption (physical adsorption) and chemisorption (chemical
adsorption).
• The difference between physical and chemical adsorption are as
follow.

7. Physical adsorption Chemical adsorption
Reversible Irreversible
Weak van der wall forces Strong chemical bond
Hydrogen bonding and weak electronic Covalent bond
Nonspecific More specific
Common in low temperature Occurs in high temperature
Heat of adsorption is low (20 to 40 kj/mol) Heat of adsorption is high (40 to 400 kj / mol)
Example is adsorption of gases or charcoal Examples are adsorption of oxygen on silver or gold

8. Thank you!