solubilization by nouman farooq ( lahore pharmacy college )
TRANSCRIPT
SOLUBILIZATION
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Presented byNouman Farooq
Roll No. 68Pharm-D (1st Proff)
PharmaceuticsLahore Pharmacy College,
LMDC
Guided byMs. Kanwal
CONTENTS
• Introduction• Solubilization & its Importance• Mechanism of solubilization• Factors affecting solubilization• Solubilization Techniques
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Difference BetweenSolubility &
Solubilization
These are two different terms.
Solubility
• Maximum quantity of solute that can dissolve at CTP.
• Amount of Solute -> Solvent = Solubility of the substance
Expression for approximate solubility
Descriptive terms Relative amounts of solvents to dissolve 1 part of solute
Very soluble Less than 1
Freely soluble From 1-10
Soluble From 10-30
Sparingly soluble From 30-100
Slightly soluble From 100-1000
Very slightly soluble From 1000-10,000
Insoluble or practically insoluble More than 10,000
Problems with poor solubility
• Reduced drug efficiency • Reduced absorption of drug • May cause side effects
Solubilization• Physico-Chemical Property.
Solubilization definition • Thermodynamically stable solution • Addition of a component
SOLUBILIZATION
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Process of Solubilization
• Breaking of inter-ionic or inter–molecular bonds in the solute.
• Separation of solvent molecules.• Interaction.
Process of Solubilization
Process of Solubilization
Process of Solubilization
IMPORTANCE OF SOLUBILIZATION
An understanding of the solubility behavior of a drug is very important.• Parenteral formulations.• Oral formulations -> adequate solubility and
dissolution rate is required.• For entrance in systemic circulation.• Therapeutic effect.
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FACTORS AFFECTING SOLUBILITY
SOLUBILITY
TEMPERATURE
PRESSURE
NATURE OF SOLID
PARTICLE SIZE
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Factors affecting solubility:-
Particle Size: Kelvin equation
Where, S =is the solubility of infinitely large
particles S=is the solubility of fine particles
V= is molar volume γ= is the surface tension of the solid
r =is the radius of the fine particle
Temperature
• ∆Hs( heat of solution) = mole of solute is dissolved.
• Endothermic -> increases solubility.• Exothermic , decreases solubility.
Pressure
Pressure will affect solubility .• Gaseous solutes X Solubility• Solid and liquid = No effect .
Nature of the solid
Internal structure affects the solubility.• Crystalline = Low solubility.• Amorphous = High solubility.
Polymorphism
• The order for dissolution of different solid forms of a drug is in the next slide
Order of Dissociation of different solid form of drug
• Amorphous Form
• Metastable Polymorphous
• Stable Polymer
Solubilization techniques
I .PHYSICAL MODIFICATIONS A. Particle size reduction a. Micronization b. Nano suspension B. Modification of the crystal habit a. Polymorphs b. Pseudo polymorphs C. Drug dispersion in carriers a. Eutectic mixtures b. Solid dispersions c. Solid solutions D. Complexation a. Use of complexing agents E. Solubilization by surfactants a. Micro emulsions b. Self micro emulsifying drug delivery systems
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II. Chemical Modifications a. Changing in pH b. Using of salts
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CO-solvency
Enhancing weak electrolytes and non-polar solubility.• Addition of water miscible solvents is known
as co-solvency. • Formulation of parenteral.
• Ethanol, Sorbitol, Glycerin, Polyethylene glycol, propylene glycol etc.
CO-solvency
co-solvency is by • Interfacial tension• Contact angle• Polarity of the drug and water system
Example: Phenobarbitone is relatively insoluble in water but it solubility can be increased by using mixture of solvents like water, alcohol and glycerin
Addition of Surfactants
Enhance• Dissolution rate• Permeability of the drug Surfactants
• Surface tension • Micelles
Solid dispersion technique
• Particle size reduction• Increased rates of dissolution
Complexation• Reversible association of a substrate and
ligand molecule.
• Cyclo-dextrins, caffeine, urea.
Pharmaceutical Applications of Solubilization
• Wide Range.• Oil Synthesis. E.g. polysorbates 60
• Low solubility -> a problem.
Pharmaceutical Applications of Solubilization
• Compound-surfactant systems
e.g. iodine-surfactant system
Immediate availability.Oral bioavailability.Bioavailability & solubilityPossibilitiesDesirable dosage form. BackboneResearch
CONCLUSION
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