Ideal solubility parameter (solubility of drug part 2)

Ideal solubility parameter (solubility of drug part 2)

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  IIIrd Semesester B.pharmacy Physical Pharmaceutics-I Unit-I Solubility of drugs(Part-2) (Ideal Solubility Parameter)
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  THANK YOU!
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   IDAEAL SOLUBILITYPARAMETER • 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
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  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.
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  • Cohesive energydensity(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
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  • In 1936Joel 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.
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   HANSEN SOLUBILITYPARAMETER • 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.