TB2 - Marta Roldo

• For emulsions what is required ? - 4 points 


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• What are Pharmaceutical emulsions - 6 points ? 


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• What are the 3 Emulsion types ? Oil in water (o/w) -2 points , Water in oil (w/o) - 3 points , Water in oil in water (w/o/w) - 1 point 


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• Identification of emulsion type - O/W emulsions

  W/O emulsions . Talk about the difference in Miscibility , Addition of oil soluble dye (macroscopic examination) , Addition of oil soluble dye (microscopic examination), Conductivity


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• What three things make an emulsion ?

  Oil phase

  Water Phase

  Emulsifying agent
• What is the Emulsion type determined by solubility of emulsifying agent: - 2 points

  •More soluble in water then o/w

  •More soluble in oil then w/o
• What are the 6 Emulsifying agents ideal properties :

  •Colourless

  •Odourless

  •Tasteless

  •Non-toxic

  •Non-irritant

  •Produce stable emulsion at low concentration
• This is about Types of emulsifying agents: Natural Polysaccharides . - 5 points

  •Acacia

  •Forms a thick film at interface between oil and water to prevent coalescence

  •Best for oral emulsions, too sticky for external use.

  •Tragacanth – increases viscosity and prevents creaming

  •Pectin, starch, carrageenan can stabilise emulsions.
• This is about Types of emulsifying agents: Natural •Semisynthetic polysaccharides - 1 point .

  •Low viscosity methylcellulose and carboxymethylcellulose will form o/w suspension
• This is about Types of emulsifying agents: Natural •Sterol containing substances - 2 points

  •Beeswax, wool fat and wool alcohol

  •Act to form w/o emulsions
• This is about Types of emulsifying agents: synthetic . Talk about the surfactant types Anionic , Cationic and Non - ionic and what it interacts with , active form , Stable at PH . 


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• What do you need when Choosing an emulsifying agent - 9 points 


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• This is about HLB value and type of emulsion . so what surfactant is HLB < 9 , HLB between 9 and 11 and HLB> 11 .

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• This is about Formulation of emulsions , what are the different types - 7 points

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• This is about Formulation of emulsions Antimicrobial preservatives - 6 points 


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• This is about Stability of emulsions - 4 points ? 


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• Ingredients used in skin preparations - water phase - 7 points 


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• Ingredients used in skin preparations oil phase - 9 points 


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• What is emulsifying agents w/o emulsifiers ? - 6 points

  •Wool fat (from sheep wool), pale yellow sticky

  •Fatty acid esters, cholesterol and other sterols and alcohols

  •In USA it is called lanolin

  •Hydrous wool fat

  •7 parts wool fat and 3 parts water

  •Beeswax
• What is emulsifying agents o/w emulsifiers ? - 7 points

  •Emulsifying waxes

  •Anionic : Sodium lauryl sulphate (Emulsifying wax BP)

  •Cationic : Cetrimide (Cetrimide Emulsifying Wax)

  •Non-ionic : Cetomacrogol 1000 (Cetomacrogol Emulsifying Wax)

  All 3 are waxy solids and produce o/w emulsion with addition of water

  •Cetostearyl alcohol

  Varying amount of cetostearyl alcohol varies the consistency, as well as oil to water ratio
• Ointments - 2 points ?


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• What do suspensions contain ?

  •Contains one or more insoluble medicaments in a vehicle, with other additives e.g. preservatives, flavours, colours, buffers etc.
• Most pharmaceutical suspensions are aqueous but some have an ?

  oily vehicle
• What 5 things are suspensions used for ?

  •Used for oral administration, inhalation, topical application, ophthalmic preparations, and as aerosols.
• Disperse system in which one substance (the disperse phase) is distributed in ?

  •particulate form (thus insoluble) throughout the other phase (continuous phase)
• Coarse dispersion – ?

  •particles > 1μm
• Colloidal dispersion – ?

  •particles < 1 μm
• In suspensions •Particles may settle out on standing what doe sthis mean ?

  •May cause problems with redispersion - caking
• Drugs with low solubility can be formulated as ?

  Suspensions
• If something is Easier to swallow than solid dosage form what does this mean for patients ?

  •Improved patient acceptability
• Drugs with unpleasant taste in soluble form can be formulated in more ? 


  palatable insoluble form
• •Rate of absorption faster than from solid oral dosage form

  However, increased viscosity will ?

  decrease release of drug
• Insoluble form may be more stable – not degraded in ?

  presence of water
• If drug is unstable when in contact with vehicle, prepare ?

  fresh before dispensing
• Drugs unstable in aqueous vehicle may be suspended in ?

  Oil
• Bulky, insoluble powders easier to take when formulated as ?

  Suspension
• Intramuscular, intra-articular or subcutaneous injections are often formulated as ? - 2 points

  •suspensions to prolong release

  •Depot injections
• Lotions formulated as suspensions leave a ? - 2

  •thin coating on skin

  •Vehicle evaporates and leaves solid behind with cooling effect
• Properties of a good suspension ? - 4

  •Ready redispersion of sediment which forms during storage

  •After shaking, particles stay in suspension long enough for accurate dose

  •Suspension is pourable

  Suspension is free from gritty texture – particles are small
• Formulation of suspensions ? - 4

  •Control of particle size

  •Grind ingredients to fine powder with mortar and pestle

  •Use a thickening agent to increase viscosity (suspending agent)

  •Use a wetting agent