Antioxidants for use in oral preparation should also

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Antioxidants for use in oral preparation should also be odorless and tasteless. 08/09/19 PHT 312 32
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Antioxidants Gallic acid, Propyl gallate - pharmaceuticals and cosmetics - Bitter taste Ascorbic acid – Suitable for oral use products Sulphites - Suitable for oral use products L-tocopherol - pharmaceuticals and cosmetics -Suitable for oral preparations e.g. those containing vit A Butylated hydroxyl toluene - pharmaceuticals and cosmetics - Pronounced odor, to be used at low conc. Butylated hydroxylanisol - pharmaceuticals and cosmetics 08/09/19 PHT 312 33
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Preparation of Emulsions Preparation Of Emulsions Preparation of emulsions depends on the scale at which it is produced. On small scale mortar and pestle can be used but its efficiency is limited. To overcome these drawback small electric mixers can be used although care must be exercised to avoid excessive entrapment of air. For large scale production mechanical stirrers are used to provide controlled agitation and shearing stress to produce stable emulsions. 08/09/19 PHT 312 34
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The methods commonly used to prepare emulsions can be divided into two categories : A- Trituration Method This method consists of dry gum method and wet gum method. 1- Dry Gum Method In this method the oil is first triturated with gum with a little amount of water to form the primary emulsion. The trituration is continued till a characteristic ‘clicking’ sound is heard and a thick white cream is formed. Once the primary emulsion is formed, the remaining quantity of water is slowly added to form the final emulsion. 08/09/19 PHT 312 35
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2- Wet Gum Method As the name implies, in this method first gum and water are triturated together to form a mucilage. The required quantity of oil is then added gradually in small proportions with thorough trituration to form the primary emulsion. Once the primary emulsion has been formed remaining quantity of water is added to make the final emulsion. 08/09/19 PHT 312 36
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B- Bottle Method This method is employed for preparing emulsions containing volatile and other non-viscous oils. Both dry gum and wet gum methods can be employed for the preparation. As volatile oils have a low viscosity as compared to fixed oils, they require comparatively large quantity of gum for emulsification. In this method, oil or water is first shaken thoroughly and vigorously with the calculated amount of gum. Once this has emulsified completely, the second liquid (either oil or water) is then added all at once and the bottle is again shaken vigorously to form the primary emulsion. More of water is added in small portions with constant agitation after each addition to produce the final volume. 08/09/19 PHT 312 37
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Preparation of emulsions- large scale Heat : Emulsification by vaporization Emulsification by phase inversion Low energy emulsification 08/09/19 PHT 312 38
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Preparation of emulsions Mechanical equipment for emulsification (Agitation) Mechanical stirrers Propeller type mixers -Turbine mixers - Homogenizers Colloid mills Ultrasonifiers 08/09/19 PHT 312 39
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08/09/19 PHT 312 40 40 Mechanical stirrers
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Colloidal mill 08/09/19 PHT 312 41
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Homogeniser 08/09/19 PHT 312 42
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  • Fall '19
  • Emulsion, Examples, PHARMACEUTICAL EMULSIONS

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