1. SOLUBILITY
By
S.Rakesh
M.Pharm
Discovery Biology
DMPK Department

2. CONTENTS
 INTRODUCTION
 PROCESS OF SOLUBILIZATION
 IMPORTENCE OF SOLUBILITY
 DETERMINATION OF SOLUBILITY
 FACTORS EFFECTING SOLUBILITY
 TECHNIQUES OF SOLUBILITY ENHANCEMENT

3. INTRODUCTION
 DEFINITION:
The amount of substance (solute) that dissolves in a unit volume of a liquid
substance(solvent) to form a homogenous saturated solution under
specific conditions of temperature and pressure this phenomenon is known
is solubility.
The solubility of a drug is represented as parts, percentage, molarity,
molality.

4. The Indian Pharmacopeia Provides General
terms to describes a solubility given range:

5. Depending up on solubility and permeability drugs are classified into
four classes They are as follows:

6. PROCESS OF SOLUBILIZATION
Step 1: Holes open in the solvent
Step2: Molecules of the solid breaks away from the bulk
Step 3:The freed solid molecule is integrated into the hole in the solvent

7. IMPORTENCE OF SOLUBILITY
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Therapeutic effectiveness of a drug depends upon the bioavailability and
ultimately upon the solubility of drug molecules
Solubility is one of the important parameter to achieve desired
concentration of drug in systemic circulation for pharmacological
response.
Low aqueous solubility is a major problem encountered with formulation
development of new chemical entities.
Any drug to be absorb must be present in the form of an aqueous solution
at the sight of absorption.
Most of the drugs are weakly acidic or basic having poor aqueous
solubility .
More than 40% of NCEs developed in pharmaceutical industry are
particularly insoluble in water.

8. Continued
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These poorly water soluble drugs having slow drug absorption leads to
inadequate and variable bioavailability and GIT mucosal toxicity.

9. DETERMINATION OF SOLUBILITY
 Thermodynamic
solubility
 Kinetic solubility

10. Thermodynamic solubility:
Kinetic solubility:

11. FACTORS EFFECTING SOLUBILITY

12. TECHNIQUES OF SOLUBILITY
ENHANCEMENT