extraction dr. basavaraj k. nanjwade m. pharm., ph. d department of pharmaceutics faculty of...
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EXTRACTIONDr. Basavaraj K. Nanjwade M. Pharm., Ph. D
Department of PharmaceuticsFaculty of Pharmacy
Omer Al-Mukhtar UniversityTobruk, Libya.
E-mail: [email protected]
2014/05/20 1Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
CONTENTS
Brief notes concerning:
• Partition
• Leaching
• Equipments
• Reference
2014/05/20 2Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Definition
• Extraction may be defined as the treatment of the plant or animal tissues with solvent, whereby the medicinally active constituents are dissolved and most of the inert matter remains undisclosed.
• The solvent used for extraction is known as “Menstrum” and the inert insoluble material that remains after extraction is called “Marc”.
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Partition(Liquid-liquid extraction)
• The term partitioning is commonly used to refer to the underlying chemical and physical processes involved in liquid–liquid extraction but may be fully synonymous. The term solvent extraction can also refer to the separation of a substance from a mixture by preferentially dissolving that substance in a suitable solvent. In that case, a soluble compound is separated from an insoluble compound or a complex matrix
2014/05/20 4Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
• Leaching is a liquid-solid operation.
• The two phases are in intimate contact, the solute(s) can diffuse from the solid to the liquid phase, which causes a separation of the components originally in the solid.
• A special leaching process, when an undesirable component is removed from a solid with water, is called washing.
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Leaching(Solid-liquid extraction)
Equipments1. Infusion
2. Decoction
3. Maceration
4. Percolation
5. Digestion
The various preparations prepared by using one of above methods are Infusions, Decoctions, spirits, Elixirs, Extracts etc. All these preparations are commonly knowns as ‘Galenicals’.
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1. Infusion
• It consists of pouring water over the drugs and then allowing it to keep in contact with water for the stated period, usually 15 minutes, with occasional stirring and finally filtering off the liquid. The marc is not pressed. The boiling water is commonly used as a solvent, since it has a greater solvent action than cold water.
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2. Decoction
• In this process, the drug is boiled with water for a stated period usually 10 minutes. After boiling, the liquid is strained and water is passed through the content of the strainer to make the required volume.
• This process is mainly used for vegetable drugs of hard and woody nature having thermostable water soluble constituents.
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3. Maceration
• In this method the powdered plant material is soaked in an organic solvent for a period of time with constant or occasional stirring. The supernatant liquid (extract) is then decanted and filtered. The process is repeated for complete extraction.
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4. Percolation
• This method uses a percolator. The powdered material is packed in the percolator. Enough solvent is then poured to soak the powder. Then more solvent is poured and allowed to percolate through the material. The extract is collected in a receiver. The process is continued until extraction is complete.
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4. Percolation Percolator
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Soxhlet extraction• This is a continuous process of extraction with a hot
solvent.• Soxhlet extractors are used for this purpose. This extractor
is provided with a siphoning system.• The powdered plant material is packed in a thimble.• The solvent is boiled in a flask. The evaporated solvent
passes through the side tube of the extractor and condensed in the condenser, fitted at the top of the extractor.
• The condensed hot solvent runs into the thimble and soaks the material & extracts the constituents.
• When the chamber holding the thimble becomes full the solvent siphons down to the flask and the process is continuously repeated till extraction is complete
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Soxhlet apparatus
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5. Digestion• In digestion process, the drug is extracted by heating at a
particular pressure. This will increase the penetration power of the menstruum, so that there is complete extraction of the drug. Percautions should be taken so that the increased temperature may not harm the active constituents of the drug.
• The apparatus know as “Digestor” is used for extraction of the drug by this method. It is a vessel made up of metal. The whole of the drug along with the menstruum is placed in the body of the digestor. Place the cover over it and bolt it with the help of nuts. The drug is treated with menstruum for a definite period under specified conditions of temperature and pressure.
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THANK YOUe-mail: [email protected]
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