Solubilization

presentation on solubilization, solubilization mechanism, solubility,surfactant, types of surfactant, micelle, micelle formation and its types

1. SOLUBILIZATION by; Sanjay Kumar (DE_073) To: DR_TEHMINA _ADNAN Physical pharmacy

2. The process of S olubilization invo lves the breaking of inter-ionic or intermolecular bonds in the solute, the separation of the molecules of the solvent to provide space in the solvent for the solute, interaction between the solvent and the solute molecule or ion. . SOLUBILIATION:

3. MECHANISM OF SOLUBILIZATION: B reak up of solute-solute intermolecular bonds. Break up of solvent-solvent intermolecular bonds. Formation of cavity in solvent phase large enough to accommodate solute particles. Transfer of solute into cavity of solvent phase. Formation of solute –solvent intermolecular forces.

4. Solubility; Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. IN QUANTITATIVE WAY : Concentration of solute ion a saturated solution at a certain temperature. IN QUALITATIVE WAY : Spontaneous interaction of two or more substances to form homogenous molecular dispersion

5. surfactant Surfactants are chemical species that act as wetting agents to lower  the surface tension  of a  liquid  and allow for increased spread ability STRUCTURE OF SURFACTANTS Surfactant molecules are usually organic compounds that contain hydrophobic groups or " tails " and hydrophilic groups or " heads .“ EXAMPLE Sodium stearate 4-(5-dodecyl) benzenesulfonate alkyl ether phosphates benzalkaonium chloride ( BAC)

6. Types of surfactant; There are four types of surfactants. Anionic, Nonionic, Cationic, Zwitter ( amphoteric ) ion .

7. Nonionic surfactant have no ions . derive their polarity from having an oxygen rich portion of the molecule at one end and a large organic molecule at the other end. EXAMPLE : alcohol ethoxylates , nonylphenoxy polyethylenoxy alcohols, and ethylene oxide/propylene oxide block copolymers

8. Cationic surfactant Are positively charged molecules usually derived from nitrogen compounds . Not commonly used as cleaning agents . Many cationic surfactants have bactericidal or other sanitizing properties. Cationic surfactants are usually incompatible with anionic surfactants, because they will react with the negatively charged anionic surfactant to form an insoluble or ineffective compound.

9. Amphoteric ( zwitter ) ionic surfactant Change their charge with pH . They can be anionic, nonionic, or cationic depending on pH.   For the amphoteric surfactants the charge of the hydrophilic part is controlled by the pH of the solution. They can act as anionic surfactant in an alkalic solution or as cationic surfactant in an acidic solution.

10. MICELLE Are made out of amphipathic molecules. A micelle is a ball that forms when amphipathic molecules are put in a liquid. The liquid can be polar like water or non-polar like butane or octane. Micelles will form because only one end of the amphipathic molecules will be compatible with the liquid. 

11. In the aqueous system the high interfacial energy between the water molecules and the hydrocarbon chains of the surfactant is the primary factor in the process, while in a nonpolar system the attractive interaction between the polar parts serves as the force governing the association process. The micellization in aqueous solutions may be perceived as a phase separation that is modified through geometrical restrictions, while the corresponding phenomenon in oils is a chemical equilibrium similar to that of alcohols in such media. The consequence of this difference is that the process in water is highly cooperative and the designation of a critical micellization concentration ( cmc ) is justified. In the nonpolar environment, on the other hand, the association process is gradual and the term cmc is not warranted. In this case the interactions leading to the micellization are amenable to analysis by spectroscopic methods. Micelle FORMATION

12. TYPES OF MICELLE Following are three types of micelles Spherical micelle, Rod shaped micelle, Laminar micelle ,

13. SPHERICAL MICELLE Amphipatic can form bilayers that sandwich the tails in the middle, or they can form spherical micelles. Phospholipids are amphipathic molecules that contain two water-fearing tails. Phospholipids prefer to form bilayers . Fatty acids have only one water-fearing tail, so forming a micelle is easier and more stable for them

14. ROD SHAPED MICELLE Monomers are arranged in rod shape Rod formation is primarily governed by the characteristic Gibbs free energy of rod formation,  ΔG   rod . Geometrically, a rod-shaped micelle consists of a central cylindrical part of hydrocarbon radius  r   c  and of more or less hemispherical parts at the ends of hydrocarbon radius  r   s . The model includes hydrophobic, electrostatic, and steric interactions.

15. LAMINAR MICELLE Are interconvertable . In this type of micelle monomers are arranged in laminar manner. They are form at higher concentration. Initially micelles are of spherical type but as the concentration increases towards higher side leads to formation of laminar micelle.