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Basic Extraction methods
- 1. EXTRACTION METHODS • Preseted by;-Laxmi Kumari, B.Pharm (UIPS), Dehradun
- 2. EXTRACTION Extraction isthe process of extracting active ingredients (desired chemical constituents) from the crude drugs using a liquid solvent. It is the separation of medicinally active tissues from inert or inactive components in plants or animals using specific solvents. Solvent Can be Polar or Non-polar Depends on the nature of secondary metabolite • Example; Polar Solvent Non-polar Solvent • Water • Benzene • Alcohol • Chloroform • Acetone • Diethyl ether
- 3. IDEAL PROPERTIESOFTHE SOLVENT Must be highly selective for the compound to be extracted Inert with the extracted compound or with other compounds in the plant material Cost effective Be harmless to man & eco-friendly CHOICE OF EXTRACTION METHODS DEPENDS ON; Size of Sample Quantity of the extract required Choice of solvent The time taken for extraction Cost
- 4. STEPS FOREXTRACTION; 4 Collection of fresh plant material Drying Powder Extraction
- 5. 5 TERMS USED INEXTRACTION MENSTRUUM; Solvent or solvent mixture used for extraction. MISCELLA /Extract; Solution containing extracted substances. MARC; Inert insoluble material that remains after extraction. 5
- 6. DRYING OFCRUDE DRUGS; 6 To prevent microbiological contamination, it is necessary. Drugs should be dried below 60°C unless otherwise specified. • Lowered heat exposure • Less chance to chemical alteration Shade drying • Use less intense sun light • Economic, Most efficient Sun drying • Less explored yet • Expensive, Used for expensive drugs Far infrared drying • Low Pressure rapid drying method • For thermolabile compounds Vacuum Drying • Often used Oven/Hot air drying
- 7. 7 Size reduction • Maximumsurface area • Mesh size is 30-40 optimum Extraction • Maceration, Infusion, Percolation, soxhlation etc. Filtration • With the help of musciline cloth, filter paper, filter press Concentration • By evaporation of solvent Drying • Spray drying
- 8. 8 Extraction; Extractionis the process of efficiently dissolving & separating the desired chemical constituents from the crude drug with the use of solvent. Types Of Extraction 1. Solid Extraction The name refers to the separation of solid components from solid substance by using appropriate solvent. This type of extraction is generally performed before any further separation or processing.. 2. Solvent Extraction The liquid-liquid extraction is one in which phytoconstituents that are extracted by solid extraction process are partitioned between any two immiscible solvents. Ideally this process needs to be carried out after solid extraction process & it is considered as purification process. On a laboratory scale Solvent extraction is carried out in a separating funnel.
- 9. Mechanism OfExtraction 9 During the extraction of phytoconstituents from the plant material; • Initially solvent penetrates into the solid matrix, • After that, the solubilisation of solutes in the solvent takes place, • Later on the solute (soluble phytoconstituents ) diffuses out of the solid matrix, • And finally extracted solute are separated out by solvent evaporation. Factors Affecting Extraction Of Crude Drugs 1. The quantity & the chemical nature of the drug 2. Nature and volume of the solvents 3. Particle size of the powder of crude drug 4. Ratio of the mixing of Solvent to the sample 5. Duration of extraction 6. Temperature at which extraction is carried out 7. pH of the extracting solvent 8. Lipophilicity of the solvent mixture
- 10. 10 Conventional methods of extraction Infusion Coldinfusion Hot infusion Decoction Maceration Simple Maceration Maceration with adjustment Multiple Maceration Percolation Simple Percolation Percolation process for concentrated preparation Reserve Percolation process Modified Percolation process Continuous Percolation process Digestion
- 11. 11 1. INFUSION Verysimple method of extraction Used for volatile ingredients, vitamins , & soft ingredients Water (Cold or Hot) used as a solvent Only applicable for Soft drugs & drug containing water soluble constituents The aqueous solution of active constituents of a crude drug is termed as Fresh Infusion. Note;- Cold water is used as menstruum (solvent) in Cold Infusion while Hot/ boiling water is used as menstruum in Hot Infusion but the drug not boiled Drug + menstruum (Cold/ boiling Water) Stand for stated period (usually 15 – 20 min & sometimes over night) Shaking or occasional stirring is done if required Filtered & the marc is not pressed Filtrate is called Infusion Example;- Cold infusion of cumin & Hot infusion of lepton green tea, etc.
- 12. 2. DECOCTION 12 Crudedrug is boiled in a specified volume of water for a stated time period (10-15min) & then filtered. Suitable for drugs that are hard and woody in nature such as seed, wood etc. containing thermo-stable chemical constituents. Mainly useful for making Herbal Tea. Drug + Menstruum ( Water) Boiled for specified time Filtered & Marc is pressed Filtrate is called Decoction
- 13. 13 3. MACERATION Inthis method of extraction the crushed or powdered crude drug is soaked in the suitable solvent. The extraction time can vary from several minutes to weeks with occasional shaking or stirring at room temperature. This process is normally used for the preparation of tinctures or extracts & menstruum is usually alcoholic, hydroalcohlic in case of tincture or may be aqueous. The drug extracted by this process are either organized or unorganized drugs. I. Simple maceration - A process for tinctures made from organized drugs e.g. roots, stems, leaves etc. II. Maceration with adjustment - A process for tinctures made from unorganized drugs such as oleo-resins and gum resins. The marc is not pressed. III. Multiple maceration - A process to prepare concentrated extract. It includes ‘Double maceration’ and ‘Triple maceration’. Types of Maceration Example;- Tincture of Benzoin etc.
- 14. 14 Process ofMaceration; Solid sample + Menstruum In a closed vessel Stand for 7 days Shaking of stirring Mixing the liquid obtained The mixture is strained & the marc is pressed
- 15. 15 This processis a modified form of maceration where 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. The apparatus is known as ‘Digestor’ is a vessel made up of metal. The drug is treated with menstruum for a definite period under specified condition of temperature and pressure. i) No solvent residues ii) Eco-friendly extraction procedure 4. DIGESTION 5. Percolation Percolation means ‘pass through’. It implies a slow passage of the menstruum under the influence of gravity through the drug powder & during this movement it goes on extracting the drug molecules layer wise. In this process the drug plant material is extracted by fresh solvent. The extraction is continued until the sufficient compound is extracted. If necessary, the same material can be re-extracted with a second solvent. This method is suitable for heat-sensitive, hard & woody drugs, not suitable for drug which may block the percolator.
- 16. 16 Types ofPercolation 1. Simple Percolation 2. Reserved Percolation 3. Hot Percolation Example;- Preparation which are made by Simple Percolation • Tincture of belladonna • Compound tincture of cardamom • Strong tincture of ginger A percolator ( a narrow , cone-shaped vessel open at both ends ) is generally used. The process consist of three steps;- I. Imbibition; Moistening the drug with a little Menstruum for 4 hours. During this period the drug swells & menstruum penetrates the cell wall. II. Maceration Moistened drug is kept in contact with the menstruum for 24 hours with occasional shaking where in the menstruum dissolves & get saturated with the soluble constituents of the crude drug. III. Percolation It consist of the downward displacement of saturated menstruum formed in the maceration & extraction of the remaining active constituents present in the sample by the slow passage of the menstruum.
- 17. 17 Process of percolation Imbibitionof the crude drug Maceration- Add sufficient amount of the menstruum above the drug & allowed to stand for 24 hrs. Percolation- Outlet opened, Percolate is collected drop wise After collecting 3/4th of the required volume of the finished product, marc is pressed Percolating the liquid while mixing it. Add sufficient menstruum to produce the required volume Following a period of standing, the combined liquid is filtrated. Imbibed/moistened drug packed up to 2/3rd capacity of the Percolator Add sufficient amount of menstruum to saturate the material When the liquid comes to drop from the percolator, close the outlet
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- 19. 19 CONTINUOUS HOTPERCOLATION PROCESS / SOXHLET EXTRACTION /SOXHLATION; This process is used for those drugs Where the penetration of the menstruum into the cellular tissues is very slow, The solute is not readily soluble into the solvent, The quantity of the menstruum is very less. Fig;- Soxhlet Extractor In such cases Soxhlet extractor is used where small volume of hot menstruum is passed over the drug and again to dissolve out the active constituents until the drug is exhausted. The process is known as Soxhlation.
- 20. 20 The plantmaterial is continually washed with new solvent during the Soxhlet extraction. However, the boiling solvent containing the extracted analytes creates the fresh solvent. Meaning that through the process of evaporation and subsequent condensation, the same amount of solvent is made to flow through the extractor that contains the drug. Working of Soxhlet Apparatus; The Coarsely powdered crud drug is placed in a porous bag or “ thimble” made of strong filter paper, which is then placed in Soxhlet extractor. Place the RBF (Round Bottom Flask) on the heating mantle with the extracting solvent added.The RBF is heated, causing the solvent vapours to condense in the condenser. Condensed vapours drip into a thimble containing crude medicine, which is then extracted. When the level of liquid in chamber rises to the top of siphon tube, the liquid contents of siphon chamber drop into flask. During each cycle, pure hot solvent dissolves some of the phytoconstituents & siphoned back to the round bottom flask.
- 21. DIFFERENCE BETWEEN MACERATIONAND PERCOLATION 21 S.NO. MACERATION PERCOLATION 1. Both drug and solvent are mixed together &kept aside for 7-14 days The solvent is allowed to pass through the column of the drug 2. Duration time is more Duration time is Less 3. There is no necessity of the drug to be packed The drug should be packed in layer to get rid of air gaps 4. More amount of menstruum is required Less amount of menstruum is required 5. Doesn’t require temperature, Except Digestion Heat is required 6. More API cannot be extracted Maximum possible amount of API can be extracted 7. The clarity of the preparation is low The clarity of the preparation is low
- 22. 22 Differences between Infusionand Decoction S.No. Component Infusion Decoction 1. Plant Soft structures (Eg: Senna Leaves) Hard Woody structures( Eg: cinchona bark) 2. Menstruum Boiling (or) Cold Water Boiling Water 3. Procedure Infusing the drug with cold or hot water Boiling the drug with water 4. Time Calculated as soon as water is added Calculated as soon as water begins to boil. 5. Adjustment of final volume No adjustment Calculated as soon as water begins to boil. 6. Apparatus Infusion earthware pot Any covered apparatus 7. Storage Used fresh within 12 Hours Used fresh and when stored in refrigerator used within few days
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