The document discusses solubility definitions, classifications, and its importance in pharmaceutical sciences. Solubility affects drug absorption, formulation development, dosage accuracy, stability, and bioavailability, and is influenced by various factors including temperature and pressure. It highlights the necessity of understanding solubility for effective drug design and delivery.

1. Shri Sadashivrao Patil Shikshan Sanstha’s
SMT. KISHORITAI BHOYAR COLLEGE OF
PHARMACY, KAMPTEE
Presenter:
Deepak Thakre
M.Pharm 1st year
Industrial Pharmacy
Department
Guided By:
Dr.Nishant Awandekar sir
HOD Industrial Pharmacy
Department
Topic: Solubility and Importance

2. Solubility Definition :
In Quantitative terms as the concentration of solute in a saturated
solution at a certain temperature.
In a Qualitative way, it can be defined as the spontaneous interaction
of two or more substances to form a homogeneous molecular
dispersion.

3. As per USP Solubility of drug can be classified as
SNo. Terms Part of solvent
required for one
part of solute
1 Very Soluble <1
2 Freely Soluble 1-10
3 Soluble 10- 30
4 Sparingly
Soluble
30 -100
5 Slightly Soluble 100-1000
6 Very Slightly
Soluble
1000-10000
7 Insoluble >10000

4. Solubility is an intrinsic material property that can be altered only by
chemical modification of the molecule.
In contrast to this, dissolution is an extrinsic material property that can be
influenced by various chemical, physical, or crystallographic means such as
complexation, particle size, surface properties, solid-state modification, or
solubilisation enhancing formulation strategies.

6. A saturated solution is one in which the solute in solution
is in equilibrium with the solid phase.
An unsaturated or subsaturated solution is one
containing the dissolved solute in a concentration
below that necessary for complete saturation at a definite
temperature.
A supersaturated solution is one that contains more of
the dissolved solute than it would normally contain at a
definite temperature, were the undissolved solute present.

7. Types of Solubilities:
1.Gas in Liquid
2.Liquid in Liquid
3.Solid in Liquid

8. Liquid in Liquid:
Frequently two or more liquids are mixed together in the
preparation of pharmaceutical solutions. For example, alcohol is
added to water to form hydroalcoholic solutions of various
concentrations.
Solid in Liquid:
When the mixture contains one or more solid substances and a
liquid, it is known as solid in a liquid solution.
Gas in Liquid :
Liquid-gas solutions are those in which the solute is in the
liquid phase and the solvent is in the gaseous phase. Camphor
in nitrogen gas is a good example of a liquid-gas solution.

9. Factors affecting Solubility:
1. Effect of Pressure
2. Effect of Temperature
3. Effect of Chemical reaction
4. Effect of electrolytes and Non- Electrolytes
Gas in liquid

10. Liquid in liquid
1. Ideal and real
solutions
2. Ternary systems
Solid in liquid
1.Ideal solution
2.Non-ideal solution
Solid in liquid

11. 1. Temperature
2. Molecular structure
3. Particle size
4. Nature of solvent and cosolvent
5. PH
6. Combined effect of solvent and pH Common ion effect
7. Effect of indifferent electrolyte
8. Effect of non-electrolytes
9. Effect of complex formation
10.Effect of solubilizing agents
Factors Affecting Solubility of Solids in Liquids:

12. Importance of Solubility:

13. Solubility is crucial in pharmaceutical science for several reasons:
Drug Absorption: Solubility affects the drug’s ability to dissolve in bodily
fluids for absorption. If a drug isn’t soluble, its bioavailability decreases,
impacting its effectiveness.
Formulation Development: Solubility helps in formulating drugs into various
dosage forms like tablets, capsules, or injections, ensuring the drug can
dissolve and be absorbed as intended.
Dosage Accuracy: Proper solubility ensures accurate dosing, as the amount of
drug available for absorption is directly related to its solubility in the body.

14. Stability and Shelf Life: Understanding solubility helps in determining the
stability and shelf life of a drug, guiding proper storage conditions.
Enhanced Drug Development: Drugs with improved solubility profiles might
have better efficacy, leading to enhanced therapeutic outcomes and reduced
side effects.
Bioavailability: Solubility impacts the drug’s bioavailability, which refers to
the amount of drug that reaches the systemic circulation and is available to
produce a therapeutic effect.

15. Other Importance :
1. Select the best solvent for a drug or a mixture of drugs.
2. Overcome problems arising during preparation of
pharmaceutical solutions.
3. Have information about the structure and
intermolecular forces of the drug.
4. Many drugs are formulated as solutions, or added as
powder or solution forms to liquids.
5. Drugs with low aqueous solubility often present
problems related to their formulation and bioavailability

16. • Martin’s Physical Pharmacy and Pharmaceutical
Sciences, Sixth Edition
• Physical Pharmacy book by Dr. S.P. Agrawal.
Reference: