Emulsions

• Emulsion

  • two-phase system in which one liquid is dispersed in the form of small globules throughout another liquid in which it is immiscible
• 3 Components:

  • Dispersed liquid/ Internal phase/ Discontinuous phase
  • Dispersion medium / External phase/ Continuous phase
  • Intermediate agent/ Emulsifying agent/ Dispersing or Stabilizing agent
• Type of Emulsifying Agent

  • Natural
  • Synthetic
• Type of Emulsifying Agent: Natural

  • Animal
  • Vegetable
• Type of Emulsifying Agent: Natural - Animal

  • gelatin, egg yolk, casein, woolfat, cholesterol
• Type of Emulsifying Agent: Natural - Vegetable

  • acacia, tragacanth, chondrus, pectin, carrageenan
• Type of Emulsifying Agent: Synthetic

  • Finely Divided Solid
  • Colloid
  • Anionic
  • Cationic
  • Non-ionic
  • Amphoteric
• Type of Emulsifying Agent: Synthetic - Finely Divided Solid

  • Mg(OH)2, Al(OH)3, and Magnesium trisilicate
• Type of Emulsifying Agent: Synthetic - Colloid

  • kaolin, bentonite magma
• Type of Emulsifying Agent: Synthetic - Anionic

  • sodium lauryl sulfate
• Type of Emulsifying Agent: Synthetic - Cationic

  • benzalkonium chloride
• Type of Emulsifying Agent: Synthetic - Non-ionic

  • PEG 400, Spans and Tween (Polysorbate)
• Type of Emulsifying Agent: Synthetic - Amphoteric

  • lecithin
• Type of Emulsion

  • Simple
  • Multiple
  • Microemulsion
• Type of Emulsion: Simple

  • o/w
  • used internally; w/o
• Type of Emulsion: Multiple or Complex or Double Emulsion

  • o/w/o - an o/w emulsion dispersed in oil
  • w/o/w - a w/o emulsion dispersed in water
• Type of Emulsion: Microemulsion

  • most stable of the three
  • dispersed phase is in very small globules
  • 100 - 1000 A (Angstrom) (1A = 0.1 nm)
• Method of Preparation:

  • Wet Gum or English
  • Dry Gum or Continental
  • Bottle or Forbes
• Method of Preparation: Wet Gum or English

  • 1 part gum is triturated with 2 parts water to form a mucilage;
  • then the 4 parts oil is added slowly, in portions, while triturating
  • after all the oil is added, the mixture is triturated for several minutes to form the primary emulsion (water, oil, and EA)
  • then other formulative ingredients (e.g. sugar, flavorant like vanilla, and essential oils) are added, then the emulsion is transferred to a graduated cylinder and brought to volume with water
• Method of Preparation: Dry Gum or Continental

  • in a mortar, the 1 part gum is levigated with the 4 parts oil until the powder is thoroughly wetted
  • then the 2 parts water are added all at once, and the mixture is vigorously and continually triturated until the primary emulsion is creamy white and produces a "crackling" sound as it is triturated (usually 3-4 minutes)
  • dilution with water or other formulative ingredients are added afterwards
• Wedgewood Mortar and Pestle

  • dry wedgewood (less brittle) or porcelain mortar and pestle
  • with rough inner surface
• Method of Preparation: Bottle or Forbes

  • this ratio between oil, water, and gum is 2:2:1
  • powdered acacia is placed in a dry powder
  • two parts of oil are added, and the mixture is thoroughly shaken in the capped container
  • a volume of water approximately equal to that of the oil is then added in portions, and the mixture is thoroughly shaken after each addition, thus forming a primary emulsion
  • then is may be diluted with water or aqueous solution of other formulative agents
• Criteria in the Selection of Emulsifier

  • should be compatible with the other formulative ingredients
  • should not interfere with the stability or efficacy of the therapeutic agent
  • should be stable and do not deteriorate in the preparation
  • should be nontoxic with respect to its intended uses
  • should possess little odor, taste, or odor
• Problems in Emulsions

  • creaming
  • breaking/cracking
  • phase inversion
• Problems in Emulsions: Creaming

  • temporary separation of the 2 phases -> shake again
• Problems in Emulsions: Breaking/Cracking

  • total separation of the 2 phase with coalescence
• Problems in Emulsions: Phase Inversion

  • change of one type of emulsion into other type, due to an addition of an electrolyte or change in emulsifying agent or temperature
  • evaporation of water; o/w -> w/o due to evaporation
• Methods of Identifying Emulsion:

  • Drop Dilution Test
  • Dye Solubility Test
  • Electric Conductivity Test
  • Fluorescence Test
• Methods of Identifying Emulsion: Drop DIlution Test

  • Add water (drop) and it should turn homogenous -> o/w
  • if freely mixes with water - o/w
  • if not diluted with water - w/o
• Methods of Identifying Emulsion: Dye Solubility Test

  • oil-soluble - sudan red - w/o
  • sudan red dye is fat/oil-soluble
  • water-soluble - amaranth green - o/w
• Methods of Identifying Emulsion: Electric Conductivity Test

  • water conducts electricity - o/w
  • o/w conducts electric current
  • w/o does not conduct electric current
• Methods of Identifying Emulsion: Fluorescence Test

  • oil can absorb UV light - w/o
  • drop of emulsion added onto a piece of paper
  • oils usually absorb UV light. Thus, if there is a presence of fluorescence due to the UV light, it means that the emulsion has a high oil content (w/o)
• Mineral Oil Emulsion

  Category: Oral Emulsion
• Mineral Oil Emulsion

  Synonyms: Liquid petrolatum emulsion
• Mineral Oil Emulsion

  Description of Final Product: It has a whitish yellow color.
• Mineral Oil Emulsion

  Use/s: the emulsion is employed as a lubricating cathartic with a usual dose of 30mL.
• Mineral Oil Emulsion

  Label: White Label with Shake Well
• Mineral Oil Emulsion

  Container: 30mL wide mouth amber bottle