Conventional Extraction Methods.pptx

Extraction methods

1. EXTRACTION

2. LEARNING OUTCOMES Describe modern methods of extraction of crude drugs. Describe application of latest techniques like Spectroscopy for the isolation, purification of crude drugs. Describe application of latest techniques for estimation of phytoconstituents. Describe application of latest techniques like chromatography for the isolation, purification of crude drugs. Describe application of latest techniques like electrophoresis for the isolation, purification of crude drugs.

3. E xtr act i on: ▶ Extraction is the method of removing active constituents from a solid or liquid by means of liquid solvent. ▶ The separation of medicinally active portions of plant or animal tissues from the inactive or inert components by using selective solvents. In this method the wanted components are dissolved by the use of selective solvents known as menstrum & undissolved part is a marc. After the extraction unwanted matter is removed. Extracts are prepared by using ethanol or other suitable solvent. ▶ Extract : Extracts can be defined as preparations of crude drugs which contain all the constituents which are soluble in the solvent.

4. ▶ Type of extracts Dry extract (Tab, cap.) E.g. belladonna extract Soft (Ointment, suppository) E.g. glycerrhiza extract. Liquid : As tincture. Marc: Solid residue obtain after extraction Menstruum : Solvent used for extraction

5. Dissolution of extractive substances out of disintegrated cells. Dissolution of extractive substances out of intact plant cell by diffusion (requires steeping and swelling) Penetration of the solvent into the plant cells and swelling of the cells. Diffusion of the dissolved extractive substances out of the cell.

6. 5 Plant constituents are usually contained inside the cells. Therefore, The solvent used for extraction must diffuse into the cell to dissolve the desired compounds whereupon the solution must pass the cell wall in the opposite direction and mix with the surrounding liquid . A n eq u i li br i u m inside the cells is es t ab li she d b e t w e e n the so l u te an d the s o lvent s u r r o u ndi n g the fragmented plant tissues

7. Ideal properties of the solvents : Be highly selective for the compound to be extracted. Not react with the extracted compound or with other compounds in the plant material Have a low price. Be harmless to man and to the environment. Should have the big capacity in relation to extractive. The density of solvent should be differen t from water density. Should have the minimum viscosity.

8. Mechanism of Extraction : 1 2 3 P lant cell s o l vent

9. Factors affecting extraction process : Nature of drug Solvent Temperature pH Particle size

10. Methods of extraction : ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ Infusion Decoction Digestion Maceration Pe r c o l a t i o n C o n t i n u ou s h o t percola t i o n – Soxhalation Modern Methods: S u p e r c r i t ic a l f l u id e x tr a c t i o n Counter current extraction M i c r o w a v e as s i s t e d e x tr a c t i o n Ultrasonication-Assisted Extraction Phytonics

11. Infusion : F resh infusions are prepared by macerating the crude drug for a short period of time with cold or boiling water. These are dilute solutions of the readily soluble constituents of crude drugs. Types of Infusion : ▶ Fresh Infusion : e.g. Infusion of orange ▶ Concentrated Infusion : e.g. Concentrated infusion of Quassia

12. Decoction : In this process, the crude drug is boiled in a specified volume of water for a defined time; it is then cooled and strained or filtered. This procedure is suitable for extracting water-soluble, heat stable constituents. e.g. Tea , Coffee

13. Digestion : T h is is a f or m of m a c e r a t i on in whi c h ge n t le h e a t is u s e d d ur i n g the p r o c e s s of e xt r a c ti o n. I t is u s e d w h e n m o de r a te l y e l e v a te d te m pe r a tu r e is n o t obj e c tio n a b l e . T h e s ol v en t e f f i c i e n c y o f the m e n s t r u u m is the r e b y i n c r e a se d . e . g . E x t r a c tio n of M o r p h ine

14. Maceration : In this process solid ingredients are placed in a stoppered container with the whole of the solvent and allowed to stand for a period of at least 3 days (3 - 7 days) with frequent agitation, until soluble matter is dissolved. The mixture is then strained (through sieves / nets), the marc pressed and the combined liquids clarified (cleaned by filtration) or by decantation, after standing.

15. Process of maceration : P l a n t M a t e r i a l ( C r u s h e d o r c u t s m a l l o r M o d e r a t el y c o a rs e p o w d e r ) P l a c e d i n a c l o s e d v e ss e l s W h o l e o f t h e s e l ec t e d s o l v e n t (Menstruum)added Al l o w e d t o s t a nd f o r s e ven d a ys s h a k i n g o c c a s i on a ll y L i q u i d s t r a i n e d o ff S o l i d re s i du e ( m a rc ) p r es s e d ( Re c ove r a s m u c h a s o cc l ud e d s o l u t i on ) ( S t r a i n e d a nd e xp res s ed l i q u i d s m i x e d ) C l a ri f i e d b y s u b s i d e n c e o r filtration E v a po r a t i on a n d C on c e n tr a t i on

16. Types of maceration : Simple maceration: for organized and unorganized Crude drug e.g . i) Tincture of Orange Tincture of Lemon Tincture of Squill Double maceration : Concentrated infusion of orange Triple maceration: The maceration process may be carried out with help of heat or stirring e.g. i) Concentrated infusion of Quassia ii) Concentrated infusion of Senna

17. SIMPLE MACERATION :- INTRODUCTION:- The extraction of the drug with a solvent with several daily shakings or stirrings at room temperature. In this type of maceration, organized drug are used. TYPES:- Kinetic maceration : is carried out at room temperature, like simple maceration, the difference being that the material is kept in constant motion. Vortical (turbo) Extraction:- The drug is stirred in the menstrum with a high-speed mixture or homogenizer

18. Factors affecting Maceration Concentration gradient (C1-C2) is affected by several factors Solid/solvent ratio: Yield decreases with constant quantity of solvent and increasing proportion of drug material. Dissolution from disintegrated cells: Particle size Steeping and swelling of plant material: Capillary dilation and increase in diffusion rate (Mucilage) Diffusion from intact plant cell: Solvent must be able to solublilize substances Temperature: increase solubility (diffusion coefficient), and decrease the viscosity pH value: Influence the selectivity of extraction (qualitative and quantitative) 7.Interaction of dissolved constituents with insoluble support material of plant 8.Degree of lipophilicity 19 9.Effect of addition of surfactants, salts and co-solvents

19. MODIFIED MACERATION:- INTRODUCTION:- In this type of maceration unorganized drug are used which have no cellular or tissue structure. eg. Gum, Resins, Gum-resins, Oleo gum-resins. Here, unorganized drugs are used because in short time complete reaction not takes place. Because of no cellular structure in unorganized drugs, soluble components are directly exposed to menstrum so the process is quicker. Here the whole procedure is like simple maceration but the final product is not collected by pressing the marc but it is adjusted to the definite volume.

20. 2 1 MULTIPLE MACERATION- The aim of multiple maceration is to achieve maximum extraction by using proteins of the total volume of menstrum for successive maceration. The volume of menstrum calculated as follows:- VACUUM MACERATION:- It employs a designed maceration vessel with arrangement for connecting it to vacuum line. Modification increase its permeability of cell walls considerably & facilitates extraction in much shorter time

21. M eri t s Small sample size. Strong swelling properties or high mucilage. Energy saving process. Demerits Not exhaustively extract the drug. It is very slow process. Solvent required is more.

22. Percolation : It is continuous downward displacement of the solvent through the bed of crude drug material to get extract. Most frequently used to extract active ingredients in the preparation of tinctures and fluid extracts. It is the method of short successive maceration or process of displacement A percolator (a narrow, cone-shaped vessel open at both ends) is generally used. c oni c al c y li n d r i c a l

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24. Steps in percolation : ▶ 1. Size reduction: The drug to be extracted is subjected to suitable degree of size reduction, usually from coarse powder to fine powder. ▶ 2. Imbibition: During imbibition the powdered drug is moistened with a suitable amount of menstruum and allowed to stand for four hours in a well closed container. ▶ 3. Packing: After imbibition the moistened drug is evenly packed into the percolator. ▶ 4. Maceration: After packing sufficient menstruum is added to saturate the material. The percolator is allowed to stand for 24 hours to macerate the drug. ▶ 5. Percolation: The lower tap is opened and liquid collected therein is allowed to drip slowly at a controlled rate until 3/4th volume of the finished product is obtained.

25. Types of Percolation : 1.Simple Percolation : Drug e.g. i) Tincture of Belladonna ii) Compound tincture of cardamom 2. Modified Percolation : ● ● ● Repeated maceration is more effective than simple. Multiple maceration – Solvent divided into equal multiple time considering the solvent retained by plant tissue. Used to prepare concentrated preparation. 200gms Imbibition For 4 hours Mac e r ation For 24 hours Percolation and collect the percolate i.e.3/4 th of the volume of finished preparation

26. 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.

27. Merits : Requires less time than maceration. Extraction of thermolabile constituents can be possible. Demerits : Requires more time than soxhalation. More solvent is required. Skilled person is required.

28. Maceration Time consuming and also extraction is not complete Not required skilled operator For certain substances which are very less soluble in solvent and requires only prolonged contact with solvent. Suitable method for less potent and cheap drugs Percolation short time and more complete extraction Skilled operator is required Special attention should be paid on particle size of material and throughout process. Suitable method for potent and costly drugs Maceration Vs Percolation

29. Soxhalation Side tube S y p hon tube Th i m b le Distillation flask Heating Mantle Con d e n s er

30. THE SOXHLET EXTRACTOR Continuous extraction of a component from a solid mixture. Boiling solvent vapors rise up through the larger side- arm. Condensed drops of solvent fall into the porous cup, dissolving out the desired component from a solid mixture. When the smaller side-arm fills to overflowing, it initiates a siphoning action. The solvent, containing the dissolved component, is siphoned into the boiler below residual solvent then drains out of the porous cup, as fresh solvent drops continue to fall into the porous cup. . . . and the cycle repeats . . .

31. Merits : ▶ ▶ ▶ ▶ ▶ Large amount of drug can be extracted with much smaller quantity of solvent. Tremendous economy in terms of time, energy & ultimately financial inputs. Small scale used a batch-process. Becomes more economical when converted into continuous extraction. Procedure on large scale. Demerits : ▶ ▶ ▶ Physical nature of drug. Solvent. Chemical constituent of drug.