Rabu, 28 November 2012

Teori Emulsi ( 2 ) / Emulsion part 2

Mechanism of Emulsifier

1. Reduce interfacial tension between the  water phase and the oil phase.
2. Reduce the interfacial free energy
3. Form a rigid film layer as a mechanical barrier to prevent  flocculation and coalescence globule

Visualization of Mechanism
        





Classification of  Emulsion

1. Synthetic emulsifier:anionik,kationik,nonioni  ( monomolecular film )
2. Hydrophilic colloid ( multimolecular film )
3. Particulate Film ( Rigid film )

Types of Emulsifier Synthesis

1. Anionic groups such as soap, triethanolamine stearate, sodium lauryl sulfate.
2. Cationic groups such as quaternary ammonium compounds
3. Nonionic group such as sorbitan fatty acid esters, polyoxyethilen sorbitan fatty acid esters

Calculation of Emulsion

Based on Hydrophilic and Lipophilic balance so-called HLB

1. HLB values ​​are large (7-15), the larger hydrophilic so easily soluble in water (Crillet / Tween 80= 15)

2. HLB values ​​are small (1-6) so that the larger lipophilic soluble in oil (Kosteran / Span 80 = 4.3)

3. Emulsifier combination of these two will form a stable emulsion HLB makes = HLB need

HLB need

1. Value needed to obtain a stable emulsion.

2. Need a proper HLB value depends on the type of emulsion is about to be made.

3. Determined by experiment.

How to Calculate HLB

Case example:
How much kosteran and crillet needed if we want to make emulsifier which has HLB need is 7.

 Kosteran HLB 4,3 = 15 - 7    =   8   = (8/10,7) x 10 = 7,5 lt
                                 7
Crillet HLB 15       =  7 - 4.3  =  2,7 = (2,7/10,7) x 10 = 2,5 lt
                                                      10,7

Make of the Emulsion

The emulsion droplets process used strirrer and High Shear Mixer


Droplet comparison of the resulting




Problems occurs when the emulsion made


1. Coalescence: Combining small and large droplets in the emulsion system, in which the emulsion layer of film rupture
 
2. Cracking: Separation of oil and water sections. (irrevesible)


3. Flocculation: Segregation droplet without damage to the emulsion films

 
4. Creaming: The process of separation of the emulsion into two parts containing one part contains more dispersed phase (reversible)


The causes of cracking on emulsion.

1. Incorrect the weighing of adjuvant

2. Incorrect the HLB need (depend on the formulation and experiment)

3. There was some particle which didn't solve neither in oil or water phase.

4. Insufficient time of mixing the formula

5. The use of electrolit as the water phase like Phospat Buffer Saline ( PBS )

6. Insufficient speed of high shear mixer 



If there is some question please feel free to fill the comment....







5 komentar:

  1. is perfluoroctane sulfonate still using in pharmacy industry in indonesia ?

    BalasHapus
  2. As long as i know the perfluorooctane sulfonate (PFOS)isn't use in pharmaceutical industry. The perfluorooctane sulfonate use in another industries such as for the food packaging, paper or textile coatings as an anionik surfactan.

    BalasHapus
  3. Komentar ini telah dihapus oleh pengarang.

    BalasHapus
    Balasan
    1. Good job friend.....as you know....emulsion is not so easy...especially, how to make stable in high temperature....

      Hapus
    2. From many literatur, emulsion will not stable in high temperature. So that it's use for the stability test design. When the emulsion stable in some a period of time ( of course the period of time is get by the research extrapolated with the real time stability test ). When the emulsion still stable in that periode time with the high temperature which is the unnormal condition ( or we can call it "accelerated stability tets), so we can conclude that the emulsion is stable.

      Hapus