•

GROUP MEMBERS

• SANA DANISH • SAMAN AFREEN • SUBAS IMTIAZ • ALISHBA JAVED

EXTRACTION TECHNIQUES • MACERATION • INFUSION • DIGESTION • DECOCTION • PERCOLATION

INTRODUCTIONINTRODUCTION

EXTRACTION PROCESS

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 undissolved.

.

• A natural product is a chemical compound or substance produced by a living organism. They may be extracted from tissues of terrestrial plants, marine organism or micro - organism fermentation.

● In that respect any biological molecule is a natural product, but in general the term is reserved for secondary metabolites (carotinoids, phytosterines, saponines,phenolic compounds, alkaloids, glycosinates, terpenes etc).

3) The extracts from plant tissue are a rich source oflead compounds for nutraceutical or pharmaceutical applications

•

GALEN

Galen was the greek anotmist .

The classes of prepartion

known as maseration,infusion,

decoction,infusion, fluid extracts .such prepartion are known as galenicals ,named after

galen , the second century physician.

The various process used for extraction are MacerationIn this process, the whole or coarsely

powdered crude drug is placed in a stoppered container with the solvent and allowed to stand at room temperature for a period of at least 3 days with frequent agitation until the soluble matter has dissolved. The mixture then is strained, the marc (the damp solid material) is pressed, and the combined liquids are clarified by filtration or decantation after standing.

GENERAL PROCEDURE

plant metarial (crushed or cut small or moderatly coarse powder ) placed in →a closed vessels whole of the →selected solvent (Mensturm )added allowed to stand for seven days →

shaking occasionally liquid strained →off solid residue (marc) pressed →(strained and expressed liquid →

mixed ) clarified by subsidence or →filteration Evaporation and →concentration .

→

Maceration process for organize and unorganize Drugs

The processes of maceratioN for organize and

unorganized drugs are slightly differ as

indicated below :-

process of organized Drugs

For example (BARKS and ROOTS )●Drug +whole menstrum ●shake occasionally during seven (7) days

●strain of the liquid and press the marc ●Mix the liquid and clerify by subsidence filteration .

●filterate is not adujsted to volume

process of unorganized Drugs Example ●Gums and resin●Drug + 4/5th (in most cases ) of menstrum

●shake occasionally during 2 to 7 days as spacified

●Decant the liquid marc is not pressed ●Filter the liquid and pass more menstrum or through filter to volume

Modifications of the general processes

• Repeated Maceration may be more than a single maceration, since an appericable amount of active principal may be be left behind in the first pressing of the marc.

• The Repeated maceration is more effiecent in cases where active consitutents are more valueable.

Double maceration

Double Maceration is used for concentrated infusion which contain volatile oil, concentrated compound Gentian Infusion.

Tripple Maceration ●Where the marc can't be pressed a process of tripple maceration is somtimes employed.

●The total volume of solvent used is however large and the second and third macerates are usually mixed and evaporated before adding to the first macerates.

Modified Large scale Maceration process

Circulatory extraction:-• The efficeny of extraction in a macertion process can be improved by arranging for the solvent to be continously circulated through drug.

• Solvent is pupmed from the bottom of the vessel to the inlet where it's distrubuted through spray nozzels, over the surface of the drug.

●The movement of the solvent reduces the boundary layers and the uniform distribution minimizez the local concentration in a shorter time.

Multiple stage Extraction• In normal maceration process extraction is inocomplete, this problem can be overcome by using a multistage process.

• The equipment needed for this method is a vessel for the drug, and a number of tanks to recive the extracted solution.

• The extractor and tanks are connected with piping and valves so that anyone of the tank may be connected to the extractor for the transfer of solution.

●Each batch of drug is treated several times with solvent the receivers contain solution with the strongest in reciever 1 and weakest in receiver 3.

Advantages.

• The drug is extracted many times.• The last treatment of the drug before it's discharged is with fresh solvent, giving maximum extraction.

• The solution is in contact with fresh drug before the removal for evaporation, giving the highest possible concentration.

Percolation

(exhaustive extraction)

Process :• Organized vegetable drug in a suitably

powdered form.• Uniform moistening of the powdered

vegetable drugs with menstruum for a period of 4hours in a separable vessel (Imbibition).

• Packed evenly into the percolator.• A piece of filter paper is placed on surface

followed by a layer of clean sand so that top layers of drugs are not disturbed.

• Sufficient menstruum is poured over the drug slowly and evenly to saturate it, keeping the tap at bottom open for passing of occluded gas to pass out.

• Sufficient menstruum is also added to maintain a small layer above the drug and allowed to stand for 24 hours.

• After maceration, the outlet is opened and solvent is percolated at a control rate with continuous addition of fresh volume.

• 75% of the volume of the finished product is collected.

• Marc is pressed and expressed liquid is added to the percolate giving 80% to 90% of the final volume.

• Volume is adjusted with calculated quantities of fresh menstruum.

• Evaporation and concentration to get finished products by applying suitable techniques and apparatus .

Modifications of the General Process of Percolation

In general process of percolation, particularly in the manufacture of concentrated preparations like liquid extracts, the following problems may arise:

• a) If the active substances are thermo-labile, evaporation of large volume of dilute percolate, may result in partial loss of the active constituents.

• b) In the case of alcohol- water mixture, evaporation results in preferential vaporization of alcohol leaving behind an almost aqueous concentrate which may not be able to retain the extracted matter in solution and hence get precipitated.

In such cases the modification in general process of percolation is required as given below:

Reserved Percolation

• In this case the extraction is done through the general

percolation procedure.• At the last, the evaporation is done under

reduced pressure in equipment like a Climbing evaporator to the consistency of a soft extract (semi solid) such that all the water is removed.

• This is then dissolved in the reserved portion which is

strongly alcoholic and easily dissolves the evaporated portion with any risk of precipitation.

Cover and Run Down Method• This is the process which combines the maceration and

percolation techniques.• This process can not be used for the materials which

contain volatile principles or those that undergo change during the evaporation stage.

• This procedure is advantageous because industrial methylated spirit may be used for extraction instead of the costly rectified spirit.

The detailed procedure is as follows:• After the imbibition stage the material is packed in a

percolator.• Macerated for few hours with suitable diluted

industrial methylated spirit.

• The liquid is run off and the bed is covered with more of the menstruum.

• Macerated as before and the second volume of the extract is collected.

• This process is repeated several times with the later weaker extracts used for extraction of a fresh batch of the drug.

• More concentrate fractions are evaporated under reduced pressure to free from the toxic methanol.

• Concentrate is diluted with water and ethanol to produce correct concentration of alcohol and active principle.

Percolators

Different types of percolators are used for

• Small Scale Extraction• Large Scale Extraction

Small scale or laboratory scale extraction The processes for the manufacture of concentrated preparations by maceration and percolations are involved in extraction followed by the evaporation of solvents. The two operations are combined in continuous extraction process.

(A) Soxhlet Apparatus

• On the laboratory scale, the apparatus consists of a flask, a soxhlet extractor and a reflux condenser.

• The raw material is usually placed in a thimble made of filter paper and inserted into the wide central tube of the extractor.

●Alternatively the drug, after imbibition with the menstruum may be packed into the extractor taking care to see that the bottom outlet for the extract is not blocked.●Solvent is placed in the flask and brought to its boiling point.

• Its vapour passes up the larger right hand tube into the upper part of the drug and then to the condenser where it condenses and drops back on to the drug.

• During its percolation, it extracts the soluble constituents.

●When the level of the extracts reaches the top level of syphon tube, the whole of the percolates syphon over into the flask. ●The process is continued until the drug is completely extracted and the extract in the flask is then processed. This extraction is series of short maceration.

(B) Official extractor (BP, IP etc.)

Such type of extraction are described in the official monographs (BP, IP etc.) and illustrated in figure given below:

• In such cases, the extraction is a continuous percolation extraction procedure.

●In this apparatus, vapour rises through the extraction chamber passing the drug container; the vapour condenses in the reflux condenser and returns through the drug taking the soluble constituents to the flask.

The limitations of this process are:

• It is not useful when the raw materials contain thermo-labile active constituents because the extraction is carried out at an elevated temperature, and the extract in the flask is also maintained in the hot condition until the process is complete.

●It can be used only with pure solvents or with solvent mixtures forming azeotropes.If an ordinary binary mixture is used as the menstruum, the composition of the vapour will be different from the liquid composition.

Large Scale Extractor• The figure given below shows a type of percolator used in the industrial scale.

• The drug is supported on a perforated metal plate covered with a layer of sacking or straw.

• The percolator is provided with a removable lid which contains portholes for packing the drug, for running in the solvent and for observing the flow of solvent.

●The outlet from the percolator is fitted with a tap and pipe line to remove the percolate for subsequent processing or to use it as a menstruum for the second percolator in series for more efficient use of the menstruum by carrying out the extraction in a countercurrent manner.

●On a small scale copper percolators were originally used but these are now largely replaced with percolators made of glass or stainless steel.

INFUSION

Infusion • infusion are the dilute solutions containing the readily -soluble constituents of drug .

• Fresh infusion ,prepare by macerating the drug for a short period in cold water or boliling water were used

.

• now infusions are usually prepared by diluting one volume of a concentrated infusion to ten volumes with water

• infusions are liable to fungus and bacterial growth , and it is necessary to dispense them within twelve hours of their prepartion

General method of preparing fresh infusion • The drug is usually coarsly powderd,very fine powder being avoided (50gm)

• moisten the drug ina suitable vessel ,provided with the cover ,with 50 ml of cold water

• Allow to stand for 15 minutes • Then add 900 ml of boling water, cover the vessel tightly.

.

• allow it to stand for 30 minutes • Then strain the mixture ,pass enough water to make the infusion measure 1000 ml

• some drugs are supplied in accuratly weighed in muslin bags for preparing specific amounts of infusion .

• if the activity of infusion is affected by the

.

• by the temprature of boling water ,cold water should be used

• As the fresh infusion don not keep well , they should be made extemporaneously and in small quantities .

prepartion of concentrated infusion

• The official monograph also recogonize certain " concentrated infusion " in which 25% alchol is added during or subsequent to the infusion process.

Factors affecting of choice of Extraction process• The final choice of the process to be used for the extraction of the drug will depend on a number of factor ,including

• Character of Drug• if hard and tough (such as nux vomica )use percolation

• if soft and parenchymatous (such as gentian )use maceration

.

• if unpowderable (such as squill) use maceration

• IF an unorganized drug (such as benzoin) use maceration

• if preferable to avoid powdering (such as senna fruits ) use maceration

Theraputic value of the Drug

• when the drug has considerable theraputic value , the maximum extraction is required ,so that percolation is used ,as in belladona .

• if the drug has little theraputic value, however, the efficency of the extraction is un important and maceration is adequate .for example , "flavours "( lemon ) or "bitters" (gentian )

Stability of the Drug

continious extraction should be avoided when the consitituents of the drug are thermo-labile

Cost of the drug

• IT is desirable to obtain complete extraction of an expensive drug, that percolation should be used, Ginger is an example of this type

• for cheap drugs the reduced efficency of maceration is acceptable in veiw of the lower cost of the process ,in particulr the cost of size reduction to a powdered state is avoided ,whereas this is a significant part of the percolation process

Solvent

• If the desired consitutent demand a solvent other than a pure boling solvent or an azeotrop , contineous extraction should be used

concentartion of product

• Dilute products such as tincuture can be made by maceration or percolation ,depanding on the previous factors

• For semi-concentrated preparation (concentarted infusion for e.g) the more efficient percolation process is used )unless the drug cannot be powdered or it is not worth powdering ,when double or triple maceration is chosen

.

• concentarted prepartion ,of which liquid extract or dry extract are the example are made exclusively by percolation ,with exception that contineous extraction can be used if the solvent is suitable and the consitituent are thermo -stable

Recovery of solvent form the marc

The residue of the drug after extraction (often known as marc ) is saturated with solvent and if economic the latter is recovered

DECOCTION

DEFINATION:

A concentrated liquor resulting from heating or boiling a substance, especially a medicinal preparation made from a plant.

PROCEDURE:

• The decoction is used for active ingredients that doesn´t modify with temperature.

•In this process the drug is boiled in water for 15 to 60 minutes (depending on the plant or the active ingredient to extract), it´s cooled,

strained and added enough cold water through the drug to obtain the desired volume.

•Depending on the consistency of the parts to extract, decoction times will be more or less long;

generally roots, leaves, flowers and leafy stems are boiled in water for about 15 minutes, while the branches and other hard parts can require up to an hour, during this time the evaporated water must be replacing.

• Once the decoction is done it´s necessary to filter the liquid through a cloth, squeezing very well the obtained liquid.

•Doses are similar to the infusion ones, ie a plant part per ten of water, except for the

•The decoctions are prepared for using in the moment and shouldn’t be stored for more than 24 hours.

●plants with high mucilage content in this case will be 1/20 to prevent the solution takes much viscosity.

• Herbal teas can be very pleasurable to drink, but can also, with regular use, tone, soothe, and balance the body. Use the decoction method of brewing tea when working with hard, woody substances (such as roots, bark, and stems) that have constituents that are water-soluble and non-volatile.

How to Make a Decoction

Steps • Understand what an herbal tea is. An herbal tea does not have tannin or caffeine, but does have varying amounts of antioxidants depending on how the herb is processed.

• 2• Understand the purpose of the decoction method. In addition to the traditional recipe for brewing tea (1-cup boiling water poured over 1-t dried herb or 2-t fresh herb), you may also choose to make an infusion (which is stronger than a tea) or a decoction.

• The decoction method is used for hard, woody substances (such as roots, bark, and stems) that have constituents that are water-soluble and non-volatile. (Red clover is an exception, because red clover flower decoction will extract more minerals that the infusion.)

• 3• Make a decoction. The basic recipe for a decoction includes 1-pt water and 1-oz of herb or root.

• Place the water into a pot made from non-reactive metal (such as stainless or enamel; do not use aluminum).

3

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● Decoctions extract mainly mineral salts and bitter principles. Decoctions are intended for immediate use.

● Store for a maximum of 72 hours in the refrigerator.

• is reduced by one-quarter (so, three-quarters of a pint remains). Cool and strain.

• Store in the fridge for no more than 72 hours .

USES

• The Cuban population performed pharmacological screening for cardiotonic, hypotensive or bronchodilator activities on 50 plant species depending on their traditional medical use. Eleven of these species may have promise as therapeutic agents,

• preclinical pharmacological and toxicological studies are needed to establish their therapeutic effectiveness and safety in human disease.

THE END