Extraction in pharmaceutics

Pharmaceutical preparationsThe process of “EXTRACTION”

12\12\2012

“EXTRACTION with Special Reference to Maceration”

Assigned by

Dr. Akhtar Rasool

Ph.D-Pharmaceutics

Presented by

Mudassar Ahmad

DPH-FA11-035

“The University of Faisalabad”

DEFINITION“Extraction involves the separation

of medicinally active portions of animal or plant tissues from the inactive components through the use of selective solvents”

INTRODUCTION

• Although, the various classes of preparations involving simple expression, aqueous hot and cold extraction and evaporation were in vogue since long time but, real and scientific rapid progress in the extraction procedures for medicinal plant's preparations was made after 19 th century.

…

• Such extraction techniques and processes were highly successful in

• the phytochemical field leading to isolation of single pure molecules

• and standardized extracts for therapeutic purposes.

…

• Simple traditional to advanced technologies conforming to official procedures are being used to manufacture different types of preparations popularly known as Galenicals.

…

• Such class of

preparations includes:

• Decoctions

• Infusions

• Fluid extracts tinctures

• Semi solid extracts

• Powdered extracts.

Various Methods of Extraction

• Maceration

• Percolation

• Infusion

• Decoction

• Digestion

…Purposes of Extraction

• The sole purpose of such basic extraction procedures for crude

• drugs are to obtained the therapeutically desirable portion and

• eliminate the inert material by treatment with a selective solvent

• known as the Menstruum.

…

• Such types of extraction procedures also play a decisive role for the qualitative and quantitative composition of the extracts.

• The standardized extracts, thus obtained are further processed for inclusion in other dosage forms such as Tablets and Capsules.

…

• These extracts are also utilized for isolation and characterization of therapeutically active chemical constituents used in modern medicines.

General Terms Used

• Menstrum: Solvent used for extraction is known as menstrum. Eg; Water, Alcohol, Ether.

• Marc: The inert fibrous and other insoluble materials remaining after extraction.

• Extracts: Preparations of liquid(Tinctures),Semisolid(soft extracts),or Solid(dry extract)

General Method of Extraction

• Communition (reducing substances to small size)

• Penetration of the crude drug by menstrum

• Dissolution of the active principles by menstrum

• Diffusion of the dissolved active principles through the cell wall to the sorrounding menstrum

• Seperaion of the dissolved active principles from the marc by filtration or expression.

Choice of Menstrum

• Highly selective for the compound to be extracted

• High capacity for extraction

• Not react with the extracted compound or with other compounds in the plant material

• Have low price

• Harmless to the man and to the environment

• Completely volatile.

Generally used Solvents

• Water

• Aliphatic alcohols with upto three Carbon atoms

• Ether

• Chloroform

• Glycerine

Difference Between Water and Alcohol

Advantages:•Cheap•Non toxic•Non Inflammable

Advantages:•Selective•No additional preservatives required•Non toxic

Disadvantages:•Non-Selective•Promote Hydrolysis•Promote enzymatic degradation•Good media for microbial growth

Disadvantages:•Costly

WATER ALCOHOL

Solvent of Choice for:•Proteins•Coloring Matter•Gums•Alkaloidal Salts•Glycosides•Sugars•Enzymes•Anthraquinone derivatives•Organic derivatives

Solvent of Choice for:•Alkaloids•Alkaloidal salts•Glycosides•Volatile Oils•Tennins•Resins

Maceration

“The process in which properly communited drug is placed or permitted to soak in a solvent for specific period of time until the cellular structure is softened and penetrated by the solvent and soluble constituents are dissolved and extracted out ’’

Example: Tea bags

Property of Maceration

“Definite quantity of drug is placed in the menstrum for definite period of time’’

Maceration Process: Following steps are involved in the general

maceration process of extraction;• Plant material (crushed or cut small or

moderately coarse powder)• Placed in a closed vessel.

• Whole of the selected solvent (menstruum) added.

• Allowed to stand for seven days, shaking occasionally.

• Liquid strained off.• Solid residue (mark) pressed (recover as much

as occluded solution).• Strained and expressed liquids mixed.• Clarified by subsidence or filtration.• Evaporation and concentration

Maceration is further carried out by following processes:

• Maceration for Organized drugs

• Maceration for unorganized drugs

• Multiple Maceration

Organized and Unorganized Drug Maceration

Maceration of Organized Drugs

Maceration of Unorganized Drugs

Drug+Entire volume of menstrum

Drug+4/5 of menstrum

Shake occasionally for 7 days

Shake occasionally on days 2-7.

Strain liquid and press the mark.

Decant liquid, marc is not pressed.

Mix the liquids and clarify by filtration. Final volume is not adjusted.

Filter the liquid and final volume is adjusted by remaining menstrum.

Eg; Vinegar of squill, oximal of squill, Tincture of orange, Tincture of lemon, Tincture of Squill.

Compound tincture of benzoin, Tincture of Myrrh, Tincture of Tolu.

Multiple Maceration:

Same as simple maceration process but the menstrum is divided into parts ( two for double and three for triple )

Double Maceration:

Drug is macerated twice, menstrum is divided into two equal parts.

Volume of menstrum required for first maceration

Total vol.of menstrum-vol. to be retained by the drug + vol. to be retained by the drug

2

Volume of menstrum required for second maceration

Total vol. of menstrum-vol.of menstrum used for first maceration

Procedure:

Drug is macerated for 48 hrs with the quantity of menstrum required for 1st maceration. Strain the liquid and press the marc. Macerate again for 48 hrs with remaining menstrum required for 2nd maceration. Strain the liquid and press the marc. Mixed the liquid obtained from two maceration. Allow it to stand for 14 days and then filter.

Large scale extraction process

Circulatory Extraction:• The efficiency of extraction in a maceration

process can be improved by arranging for the solvent to be continuously circulated through the drug, as indicated in the figure below.

• Solvent is pumped from the bottom of the vessel to the inlet where it is distributed through spray nozzles over the surface of the drug.

• The movement of the solvent reduces boundary layers, and the uniform distribution minimizes local concentration in a shorter time.

Multiple stage extraction

Procedure:• Fill extractor with drug, add solvent and circulate. Run off

to receiver 1.• Refill extractor with solvent and circulate. Run off to

receiver 2.

• Refill extractor with solvent and circulate. Run off to extractor 3.

• Remove drug from extractor and recharge. Return solvent from 1 to extractor. Remove for evaporation.

• Return solution from 2 to extracture and circulate. Run off to receiver 1.

•Return solution from 3 to extractor and circulate . Run off to receiver 2.•Add fresh solvent to extractor and circulate. Run off to receiver 3.•Remove drug from extractor and recharge. Repeat cycle.

Extraction Battery

• In the normal percolation process, the percolate is not of maximum concentration and as such very dilute.

• The ideal situation would be to have maximum concentration.

• Continuous extraction devices of this type are used where large amounts of single material are handled.

• It can be achieved by treating it as a stage wise process.

• In this process a series of vessels are used and extraction is semi–continuous.

Equipment

• Equipment is described as an extraction battery and consists of a number vessels with inter connecting pipe work.

• Vessels are so arranged that solvent can be added to and the product taken from any vessel.

• These vessels can, therefore, be made into a series with any of vessels as the first of the series.

• The use of extraction battery is illustrated in Fig. given below, where simplest arrangement of three vessel is shown