It has been observed that a stationary menstruum dissolves the more active constituents because stationary menstruum may remain in contact with more time to drug compare to the moving menstruum. Percolation is a type of displacement method. By this, we can save menstruum, time, and heat. In the modified percolation process we reduce the drug/percolate ratio to 1:3 which is generally 1:4 in the common percolation process. The process has the advantage that we obtain the concentrated menstruum without heating the major portion (three fourth portions) which have more active ingredient and just heat the last one-fourth of portions which also save energy as well as handles less amount fluid for the process. The last one-fourth portions contain very less amount active ingredients so, with the help of evaporation generally, we concentrate the menstruum. This concentrated syrupy fluid should be added into the previous three fourth portion of menstruum. In this type of percolation, the initial portion (near about three fourth of the percentage of menstruum) which has the major quantity of active ingredient is kept separate just like the simple percolation process and the last one-fourth amount of menstruum is collected in another vessel and concentrated by the method of evaporation. Example- Strong tincture of ginger, tincture of belladonna, etc.įig 1.1: Simple percolation method Reserved Percolation Allow the liquid to stand and separate the suspended particles by filtration or decantation. More menstruum should be added to obtain the desired volume. In the last, the marc should be pressed, and obtain liquid is added into the collected menstruum. Perform the specific chemical test for the last few ml of percolate like tannins, glycoside, alkaloids, etc whether it is positive or negative.Evaporate the last few ml of percolate to dryness and see if any residue comes after evaporation or not.By checking the specific gravity of the end few ml of percolate and compare with the specific gravity of fresh menstruum.Completion of the percolation process should be checked by various methods like: Meanwhile, sufficient menstruum is added over the powdered drug so that the packed drug does not become dry. Open the lower tap after 24 hours of maceration and collect the menstruum from the lower end until the three fourth portion of the final product is obtained. The menstrual level should be above the drug bed. When menstrual starts to come from a lower tap close the tap and allow to stand, the percolator for 24 hours as the primary maceration take place. During the addition of menstruum, the lower tap of the percolator should be open so that air present in the percolator is displaced by the menstruum. This prevents any type of disturbance of the crude drug by the flow of menstruum.Ī sufficient amount of menstruum should be added after packing the percolator. Two third of the percolator should be covered with the drug on which place the piece of filter paper and wash sand should be placed on the top of the filter paper. The packing should be perfect, neither too tight nor too loose which may affect the flow of menstruum. The lower end of the percolator should be plucked with cotton and then place the drug powder layer by layer. Imbibitions also prevent the washing of fine particles of the crude drug during percolation.Īfter imbibition, the lump of the crude drug must be broken. Imbibitions replace the interstices air which can otherwise affect the flow of menstruum. The swelling of the drug reduces the porosity of the powder and chokes the percolator. This initial moistening of the crude drug powder is very important because it reduces the chances of choking of percolator though the dried drug swells when comes into contact with menstruum. During this duration, the menstruum penetrates the cell wall. Imbibition is a process in which the powdered drug is kept along with menstruum for 4 hours in a well-stoppered container. Size reduction is also helpful for uniform packing of the crude drug in the percolator and reducing the moment of menstrual in the percolator. Size reduction also increases the surface area of the crude drug and more surface area of the crude drug will be available to react with the menstruum. To assure the complete exhaustion of the crude drug, the drug should be suitable size reduced. The various stages involved in the percolation are following Soxhlet Extraction/Continuous Hot Percolation Process.The various stages involved in the percolation are following.
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