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* The word 'maceration' means 'softening'. * It is used in the preparation of tinctures, extracts and concentrated infusions. * This is the simplest method of crude drug extraction and is official in Indian Pharmacopoeia. * In this process, the material to be extracted is placed in a closed vessel and suitable solvent (men strum) is added and left for 7 days with occasional shaking. The liquid is then strained off and the solid residue (Marc) is pressed to remove the solution as much as possible. The strained and expressed liquids are mixed and clarified by filtration. * The drug should be properly com minuted but fine powder should be avoided as subsequent clarification becomes difficult. * In case of vegetable and animal tissues, sufficiently long time is allowed for the men strum to diffuse through the cell wall to solubilise the constituents present within the cells and for the resulting solution to diffuse out. * Occasional shaking brings about rapid equilibrium between intra and extra cellular fluids thereby bringing fresh men strum to the particle surface for further extraction. * A closed vessel is used to prevent the loss of men strum by evaporation and avoids batch to batch variations. * The process takes 14 days for complete extraction. * The drug: men strum ratio should normally be 1:10. * The product should be allowed to stand for few days before use to allow sediment to form. * Straining may be done through a cloth and special presses are available to press the Marc. * Volume of strained liquid will be constant and the volume of expressed liquid will vary depending on the efficiency of expression. * For organized drugs, the volume is not made up but for unorganized drugs like benzoin, the strained liquid is made up to the volume. TYPES OF MACERATION: 1) MODIFIED MACERATION: * It is essentially used for extracting unorganized drugs. Ex: gums, resins etc. * Here, pressing of Marc is not done because it has no appreciable amount of macerate. * The final product is adjusted to definite volume. * This process is quick because the soluble constituents are directly exposed to men strum due to lack of cellular structure. * The process includes, * Com minute the drug with men strum * Place in closed vessel for 2-7 days, * Agitate the mixture occasionally, * Strain and filter the strained liquid, * Wash the Marc with fresh men strum using less than 20% of finished bulk and pass the washings through the same strainer and filter, * Make up the volume. * The filtrate should be collected in a dry receiver or in a receiver rinsed with men strum because the resinous matter present in most of the unorganized drugs is insoluble in water affecting the clarity of the final product. Ex: preparation of tincture of opium. 2) MULTIPLE MACERATION: * Multiple maceration is aimed at achieving maximum extraction by using portions of total volume of men strum for successive maceration. * The drug: men strum ratio is low. * The volume of men strum for each maceration can be calculated as follows, For double maceration, Volume of menstrum (total volume - vol.retained drug)/2 + for 1st maceration = vol. retained by drug. For triple maceration, Volume of men strum For 1st maceration = (total volume - vol. retained by drug)/3 + vol. retained By drug. * Efficiency of extraction increases as the number of maceration's increases. * Multiple maceration is not generally used. 3) VACUUM EXTRACTION: * This process employs a specially designed maceration vessel with arrangement for connecting it to vacuum line. * This process increases the permeability of the cell walls considerably and facilitates extraction in a much shorter time. REFERENCE: 1. Text book of Professional Pharmacy by N.K.Jain and Sharma, pg. 115.