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level: level 5

Questions and Answers List

level questions: level 5

Question	Answer
Emulsion to be applied externally can be made such that the medicinal agent that are __ may be incorporated in the internal phase	irritating to the skin surface
1 On the unbroken skin, this emulsion can usually be applied more evenly 2 if it is easily removed from the skin, this is preferred	1) W/O emulsion 2) O/W emulsion
Theories of Emulsification	1 Surface tension theory 2 Oriented Wedge Theory 3 Interfacial Film Theory
INHIBITS GLOBULE TO BREAK INTO SMALLER ONES • Use of substances as emulsifiers & stabilizers (SURFACTANTS/ WETTING AGENTS) • Results in the lowering of the interfacial tension of the 2 immiscible liquids, reducing the repellant force between the liquids • facilitate breaking up of large globule to smaller ones • lesser tendency to coalesce	Surface Tension Theory
Deals with formation of monomolecular layers of EMULSIFYING AGENT curved around a droplet of the internal phase of the emulsion	Oriented Wedge Theory
Places the emulsifying agent at the interface between oil and water, surrounding the droplets of the internal phase as a thin layer of film adsorbed on the surface of the drops. The FILM prevents the contact and the coalescence of the dispersed phase, the tougher and more pliable the film, the greater the stability of the emulsion	Plastic and Interfacial Film Theory
The method is also referred to as the “4:2:1” method because for every 4 parts (volumes) of oil, 2 parts of water and 1 part of gum are added in preparing the initial or primary emulsion	Continental or Dry gum method
Continental or Dry gum method (step by step)	1 Acacia placed in the mortar, Add the Oil 2 Mix 3) 2 parts of Water is then added 4) Mix for 3 mins 5) Other ingredients added produced primary emulsion Mnemonics: DOG AOW AOW (ACACIA, OIL, WATER) (Dog: Dry Gum)
English or Wet Gum Method (step by step)	1. Gum and water is triturated (twice its weight water) 2. Oil is added Too thick: add water 3. Other ingredients is added Mnemonics: Wolf AWO AWO (Acacia, Water, Oil) (Wolf = Wet Gum)
For the extemporaneous preparation of emulsions from volatile oils or oleaginous substances of LOW VISCOSITIES, this method is used	Bottle or Forbes bottle method (G+O+W)
Bottle or Forbes Bottle Method (G+O+W) (Step by step)	1 Powdered acacia placed in bottle 2) 2 parts of Oil added 3) Shake thoroughly 4 A volume of water approximately equal to the oil is then added in portions 5 the primary emulsion thus formed may be diluted to the proper volume with water or other an aqueous solution of other formulative agents
An emulsion by either the wet gum or dry gum methods will increased in quality by passing it through a __ In this apparatus, the pumping action of the handle forces the emulsion through a very small orifices which reduces the globules of the internal phase to about 5 um and sometime less	hand homogenizer
In SITU soap method two types of soap developed	1 Calcium soaps 2 Soft soaps
– water - in - oil emulsions – vegetable oil (e.g. Oleic acid) in combination with lime water ( Syn: Calcium Hydroxide Solution USP) – mixing equal volumes of the oil and lime water – 1:1	Calcium soaps
• Thermodynamically stable, optically transparent, isotropic mixtures of a biphasic oil-water system stabilized with surfactants. • The diameter of droplets range of 100 A (10 microns) to 1000 A whereas in a macroemulsion the droplets may be 5000 angstroms in diameter.	Microemulsions