Solubility of drug, Ideal solubility parameter, Hildebrand solubility parameter, Hansen solubility parameter

1. IIIrd Semesester B. pharmacy
Physical Pharmaceutics-I
Unit-I
Solubility of drugs(Part-2)
(Ideal Solubility Parameter)

2. THANK YOU!

3.  IDAEAL SOLUBILITY PARAMETER
• Solubility parameters provides numerical methods to predict interaction between material.
• It is used for estimation of whether substance will dissolve in another substance or not.
• If values of solubility parameter are same then we can say that one substance is soluble in another.
• Two types of solubility parameter
Hildebrand solubility parameter
Hansen solubility parameter

4. HILDEBRAND SOLUBILITY PARAMETER
• Theory of solubility parameter
 Scatchard in 1931
Joel H. Hildebrand in 1936
• Def: The solubility parameter is a numerical value that indicates relative
solvency behaviour of specific solvent.
• It is derived from the cohesive energy density of the solvent, which in turn is
derived from the heat of vapourisation.

5. • Cohesive energy density(C) is the forces of attraction per unit volume of solvent.
c=
Δ H−RT
𝑉𝑚
Where:Type equation here.
C=Cohesive energy
Δ H= Heat of vaporization
R= Gas constant
T=Temperature
Vm= molar vovume

6. • In 1936 Joel H. Hildebrand proposed the square root of the cohesive energy as a
numerical value indicate the solvency behavior of a specific solvent
• The quantity represented by the symbol δ
δ = 𝐶
• The term Hildebrand be adopted for solubility parameter units, in order to recognize
the tremendous contribution that Dr. Hildebrand has made to solubility theory.
• Values are shown in both the common form which is derived from cohesive energy
densities in calories/cc and newer from which, conforming to standard international
units (SI units), is derived form cohesive pressure. The SI units for expressing
pressure is the pascal.

8.  HANSEN SOLUBILITY PARAMETER
• The most widely accepted three component system to date is the three
parameter system developed by Charles M. Hansen in 1966.
• Hansen parameter divided the total Hildebrand value into three parts.
1. Dispersion force component,
2. A hydrogen bonding component,
3. A polar component.