Preservation of emulsions

1. UNIT-III Coarse Dispersion
EMULSIONS
Dr. A. SUMATHI
Professor & Head
Department of Pharmaceutics

2. Emulsions
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● Theories of emulsification
● Stability of emulsions
● Preservation of emulsions
● Rheological properties of emulsions
● Emulsion formulation by HLB method
● Microemulsion and multiple emulsions
Dr. A. SUMATHI
EMULSIONS

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7. Preservation of
Emulsions
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8. Preservation of Emulsions
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● Bacteria degrades non-ionic & anionic emulsifying agents and
hydrocolloids
● Therefore, a suitable antimicrobial preservative should be incorporated
in emulsions to resist microbial attack
● Preservatives are partitioned strongly in favour of oil phase so that low
concentration of preservative remain in aquoeus phase
Dr. A. SUMATHI
EMULSIONS

9. Preservation of Emulsions
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● In non-oinic emulsions, free or unbound preservatives are effective
● Eg. Sodium methyl paraben
● Sodium propyl paraben
● Sodium benzoate
● The oil phase should be protected from becoming rancid by adding
antioxidants
● Eg. α-tocopherol
Dr. A. SUMATHI
EMULSIONS

10. Special
Emulsion Systems
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11. Special Emulsion Systems
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● Multiple Emulsion
● Micro Emulsion
Dr. A. SUMATHI
EMULSIONS

12. Multiple Emulsion
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● Multiple Emulsion – Types
● O/W/O
● W/O/W
Dr. A. SUMATHI
EMULSIONS

13. Multiple Emulsion
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● Multiple Emulsion – Types
● O/W/O
● O/W emulgent (Eg?????) + Aquoeus Phase + Oil Phase slowly add
● O/W emulsion (Primary Emulsion)
● W/O emulgent (Eg…???) + Oil Phase
● O/W/O Multiple Emulsion
Dr. A. SUMATHI
EMULSIONS

14. Multiple Emulsion
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● W/O/W can be prepared by
Mix W/O emulsifying agent (Sorbiton mono oleate) with an oil phase
Add aqueous phase slowly
Formation of W/O Emulsion
Disperse in an aqueous solution of an O/W emulgent (Tween 80)
Formation of W/O/W Emulsion
Dr. A. SUMATHI
EMULSIONS
Homogeniser

15. Micro Emulsion
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● Unlike emulsions, micro emulsions appear as
● Clear transparent solution
● But unlike solution or solubilized system, microemulsion will not be
thermodynamically stable
● Globule size: 10 to 200 nm
● Volume fraction of the dispersed phase: 0.2 to 0.8
Dr. A. SUMATHI
EMULSIONS

16. Micro Emulsion
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● Micro emulsion contains
● Droplets of organic liquids in water or
● Droplets of water in organic liquids
● An anionic surfactant (Sodium lauryl sulphate or Potassium oleate)
may be dispersed in an organic liquid (Benzene)
● A measured quantity of water is added
● Then, a clear solution of microemulsion is formed by the addition of
Pentanol (Lipophilic Co-surfactant) or Pentyl alcohol
Dr. A. SUMATHI
EMULSIONS

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19. THANK YOU
Dr. A. SUMATHI
Professor & Head
Department of Pharmaceutics