GALENICAL PREPERATIONS Dr.

Sidra Noreen
University of the Punjab
 GALENICAL PREPARATIONS
Pharmaceutical preparations are divided into:
1. Galenical preparation
2. Non-Galenical preparations
GALENICAL PREPARATIONS:
Medicines prepared according to the formulae of Galen.
- galenical preparations are the medicines prepared from plant or
animal tissues, especially vegetables.
- The term is now used to denote standard preparations containing one
or more active constituents of a plant and made by a process that leaves
the inert and other undesirable constituents of the plant un-dissolved.
EXTRACTION:
Extraction is defined as the withdrawal of desired constituents from crude
drugs through the use of selected solvents in which the desired constituents are
soluble.
Removal of soluble material (liquid or solid) from an insoluble residue by
treatment with a liquid solvent is called as extraction.
Purpose:
Active constituents of natural or vegetable origin are separated by extraction.
Principle:
It is a solution process based on mass transfer.
Examples:
➢ Plant source: Emetine from Ipecac root Reserpine from Rauwolfia
Serpentina root Atropine from Belladonna leaves
➢Animal source: Cochineal from insect Coccus cacti.
THEORY OF EXTRACTION
1- Comminution (reducing substances to small size).
2- Penetration of the crude drug by the menstruum.
3- Dissolution of the active principles by the menstruum.
4- Diffusion of the dissolved active principle through the cell wall to
the surrounding menstruum.
5- Separation of the dissolved active principles from the marc by
straining, filtration or expression.
 TERMS
1. Crude drug: vegetable or animal drugs that have undergone no other
processes than collection, cleaning and drying.
2. Menstruum: Solvent used for extraction (ex. water, alcohol, ether)
3. Marc: The inert fibrous and other insoluble materials remaining after
extraction
4. Extracts/ Extractives: Concentrated preparations of vegetable or
animal drugs obtained by removal of the active constituents of the
respective drug with suitable menstruum, evaporation of all or nearly
all solvent.
5. Expression: is a method of fragrance extraction where raw materials
are
pressed, squeezed or compressed and the oils are collected.
SOLVENTS USED IN EXTRACTION PROCESSES
1. Water:
water is the solvent for proteins, colouring matter, gums, glycosides,
sugar, alkaloidal salts, enzymes and many organic acids and most of the
organic salts.
waxes, fats, fixed oils and most alkaloids are insoluble in water.
Advantages of water:
▪It is cheap
▪Has wide solvent action
▪Non toxic
▪Non inflammable
Disadvantages:
Water helps the growth of moulds and bacteria. Hence some preservatives are
needed to be added. Water can also cause hydrolysis of many substances.
2. Alcohol:
alcohol is the solvent for alkaloids, glycosides, volatile oils and resins.
alcohol doesn’t dissolve albuminous matters, gums, waxes, fats, fixed oils and
sugar.
Advantages:
Self preservative action with conc 20% or more.
Small amount of heat is required to concentrate alcoholic product.
TYPES OF EXTRACTION METHODS:
Expression
Infusion
Decoction
Maceration
Percolation
Digestion
 EXTRACTS
Extracts are concentrated preparations of vegetable or animal drugs obtained by
removal of active constituent of a drug with suitable menstruum, evaporation of all of
the solvent, and adjustment of the finally obtained powder to the prescribed standards.
Potent preparations
Extracts are made in three forms
Semi liquid extracts:
of syrupy consistency prepare without the intent of removing all or even most of
the menstruum
Pilular or Solid Extracts
All menstruum I removed leaving extract of plastic consistency. Used in plastic dosage
forms like ointments paste
Powdered extract:
Prepared to be dried by the removal of all of the menstruum and dried extract is used to
prepare powders capsules etc.
Pilular and solid extracts differ with only slight amount of solvent in pilular extracts.
 FLUID EXTRACTS
Fluid extracts are liquid preparations of vegetable drugs prepared by
percolation.
They contain alcohol as a solvent, preservative or both.
Concentrated preparation and are made in such a way that each mili
liter of the solution contains therapeutic constituent of 1g.
Concentrated and potent and because of their too bitter taste , almost
Non existent in medical practice.
Mostly used fluid extracts are modified by the addition of flavorants
and sweeteners. Or being used as source of drug to prepare syrups etc.
 MACERATION:
The term comes from Latin word meaning to soak.
The process in which the properly comminuted drug is permitted to soak
in the menstruum until cellular structure is softened and penetrated by the
menstruum and the soluble constituents are dissolved.
In the maceration process, the drug to be extracted is placed in a wide
mouthed container with menstruum in it.
The container is tightly sealed and the contents are agitated repeatedly
over a period from 2-14 days.
Alternate method is to place the drug in a porous bag that is suspended
in the upper portion of the menstruum, just like tea bag.
MACERATION
As the soluble constituents dissolve in the menstruum, they tend to settle to
the bottom because of an increase in the specific gravity of the liquid
due to added weight.
The extractive is separated from the marc by expressing the bag of
drug and washing it with additional menstruum, the washings being
added to the extractives.
If the maceration is performed with the loose drug, the marc is removed
by straining.
For the drug containing little or no cellular material such as benzoin,
aloe, tolu etc, which dissolve completely in menstruum, maceration is the
efficient method of extraction.
Usually conducted at 15 to 20˚C.
Various types of maceration process:
1. Simple maceration
2. Modified maceration (Maceration with
adjustment)
3. Multiple maceration
SIMPLE MACERATION
a process for the tinctures made from organized drugs like roots,
stems, leaves …
Apparatus – wide mouth bottle with a stopper
Method – Drug is placed with the whole of the menstruum in a
closed vessel for 7 days, shaking occasionally. After 7 days liquid
is strained and marc is pressed. The pressed liquid is mixed with
strained liquid, then filtered to make a clear liquid. Final volume is
not adjusted.
Ex:- Tincture of Orange Tincture of Lemon Tincture of Squill.
MODIFIED MACERATION
A process for the tinctures made from unorganized drugs like gums,
resins …
Apparatus – wide mouth bottle with a stopper
Method – The drug is placed with 4/5 th of the menstruum in a
closed vessel for a period of 2-7 days with occasional shaking.
After 7 days the liquid is filtered and the final volume is made up
by the remaining menstruum. The marc is not pressed.
Ex:- Tincture of Tolu Compound tincture of Benzoin Tincture of
Myrrh
MULTIPLE MACERATION:
multiple maceration is adopted to achieve maximum extraction of
active constituents from drug if the drugs having high % of active
substances. The process is carried out in the same way as simple
maceration process, but the menstruum used is divided into 2 parts
in Double maceration and 3 parts in Triple maceration .
Double maceration process
The drug is macerated twice by using the menstruum which is
divided into 2 parts, in which the same volume is used for each
maceration.
DOUBLE MACERATION PROCESS:
Procedure:
The whole drug is macerated for 48 hours with the quantity of
menstruum required for first maceration. Strain the liquid and press
the marc. Macerate again for 24 hours with the remaining
menstruum required for second menstruum. Strain the liquid and
press the marc. Mix the liquids obtained from the two macerations
and allow it to stand and then filter.
Ex:- Concentrated infusion of Orange Concentrated Compound
infusion of Chirata Concentrated Compound infusion of Gentian
PERCOLATION/EXHAUSTIVE EXTRACTION
The term percolation, from the Latin per, meaning through, and
colare meaning to strain.
A process in which a comminuted drug is extracted of its soluble
constituents by the slow passage of a suitable solvent through a
column of drug.
The drug is packed in a special apparatus termed as percolator,
with the collected extractive called the percolate.
The percolators vary greatly as to their shape, capacities,
composition and utility.
The choice of type of Percolator depends upon:
➢Nature of the drug
➢Type of product prepared
➢Quantity of drug to be extracted
General processes and steps of Percolation:
1. Preparation of the dried crude drug for percolation
a. Powdering b. Moistening
2. Packing the percolator
3. Period of Maceration
4. Percolation and collection of percolate
5. Adjustment of concentration of percolation as required
The rates of flow:
➢Percolate slowly – rate will not exceeding 1 mL of percolate/minute.
➢Percolate at a moderate rate - rate of 1 to 3mL/minute.
➢Percolate rapidly – rate of 3 to 5 mL per minute.
PRINCIPLE OF PERCOLATION
Percolation may be defined as ‘ short successive maceration ’ or ‘
extraction by the method of displacement.
The powder drug is placed in a cylindrical or conical vessel called
percolator , with a diaphragm at the base. The menstruum is
allowed to pass through a column of the drug at a regulated rate
which allows the menstruum to dissolve the active constituents and
get saturated. The combined forces of gravity and that of the
column of liquid above, impel the saturated menstruum downward.
This movement is opposed by the capillarity force. The physical
forces which play an important role in percolation include;
gravitation, adhesion, friction, capillarity, surface tension and
dissolution rate.
1. Simple percolation process
2. Percolation process for concentrated preparations
(a) Reserved percolation
(b) Modified percolation
3. Continuous hot percolation / Soxhlet Extraction / Soxhlation
SIMPLE PERCOLATION
Apparatus: Three types of apparatus are generally used, i)
Conical percolator ii) Cylindrical percolator iii) Steam jacketed
percolator [for higher temperature extraction]
It is one of important process of extraction in which drug is
moistened with menstruum sufficiently & packed in conical
percolator, excesses of menstruum is poured over the drug and
allowed to pass through or percolate for 24 hrs., marc is
pressed , filtered.
Eg:- Tincture of belladonna, compound tincture of cardamom,
strong tincture of ginger, liquid extract of nux vomica , liquid
extract of cascara sagrdas.
Size reduction
Imbibition STAGES:
Packing
Maceration
Percolation
Size reduction
The drug to be extracted is subjected to suitable degree of size
reduction, usually from coarse powder to fine powder, to
i) increase the surface area of the drug exposed to the menstruum
ii) for uniform packing of the percolator
iii) to slow down the movement of the menstruum.
iv) to ensure complete exhaustion of the drug.
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. During this period the drug swells up as the
menstruum penetrates the cell walls. The preliminary moistening of
the drug is necessary because:
i) the dried tissue swells when it comes in contact with the
menstruum but if packed in the dry condition subsequent swelling
will reduce the porosity of the material and choke the percolator
ii) the air present in the interstices is removed by menstruum, which
will otherwise disturb the packing of the percolator due to which
the menstruum will run through the channels results in inefficient
extraction
iii) it does not allow the fine particles to be washed out of the
percolator during percolation.
PACKING
After imbibition the moistened drug is evenly packed into the
percolator. Cotton wool or fibers of flax; previously moistened with
menstruum is placed on the perforated plate of the percolator. The
packing should not be too tight, it will lead to slow extraction rate.
Similarly, loose packing will allow the menstruum to pass through
quickly resulting in incomplete contact with the drug. The drug
should occupy 2/3 rd. capacity of the percolator. After packing , a
piece of filter paper is placed over top of the bed, on which small
quantity of washed sand is placed to prevent disturbance of the
packed material.
After packing, sufficient menstruum is added to saturate the
material (about 4 times of the drug). When the liquid begins to
drip from the bottom of the percolator, the tap fitted at its bottom
is closed. More menstruum is added if required, so that a shallow
layer of menstruum is maintained over the drug bed. The
percolator is allowed to stand for 24 hours to macerate the drug.
After 24 hours maceration, the lower tap is opened and liquid collected
therein is allowed to drip slowly at a controlled rate until 3/4 th volume
of the finished product is obtained. Sufficient amount of menstruum is
simultaneously added over the drug because at no time packed material
should be allowed to become dry. After collecting 3/4 th volume, the
percolate is tested for complete exhaustion of the drug by various tests.
Tests to check complete exhaustion of the drug:
ii) The specific gravity of last few ml of percolate is measured. If it is
equal to the specific gravity of the fresh menstruum the exhaustion is
taken to be complete.
iii) Specific chemical tests may be performed on the percolate for the
drugs containing alkaloids, glycosides, tannins, resins or bitter
constituents.
The marc is then pressed and the expressed liquid is added to the
already collected percolate. More menstruum is added to produce the
required volume. The liquid is then allowed to stand to settle the
suspended particles, decanted or clarified by filtration.
RESERVE PERCOLATION
In this process, the first portion (about 3/4 th of the final product)
of the percolate which contains the maximum amount of active
constituents is reserved. Subsequently, percolation is completed as
usual until the drug is exhausted but the last part (about 1/4th of
the final product) is collected separately. The second dilute part is
then evaporated to get a syrupy consistency which is then mixed
with the reserved first portion of the percolate. · Finally volume is
adjusted by adding more menstruum. Example: Liquid extract of
liquorice
ADVANTAGES
I. The reserved part of the percolate which contains the maximum
amount of dissolved active principles is not subjected to heat,
only the dilute portion is evaporated. Hence, the major portion
of the active constituents of the drug are saved from
deterioration.
II. The process is economical as the whole of the percolate is not
evaporated
CHOICE OF THE MENSTRUUM
The ideal solvent for a certain pharmacologically active constituent
Should be highly selective for the compound to be extracted.
Have a high capacity for extraction.
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.
The generally used solvents includes: Water Aliphatic alcohols with
up to three carbon atoms Ether, Chloroform, Glycerin etc.
INFUSION
Infusion is the process of extracting chemical compounds or flavors
from plant material in a solvent such as water, by allowing the
material to remain suspended in the solvent over time. An infusion is
also the name for the resultant liquid.
Infusion is also called the extract prepared as a result of infusing a
herb in a liquid. Common examples are tea coffee etc.
Drug
Crude drugs of light structure without dense tissues and containing
water-soluble constituents.
The drug may be freshly broken, thinly sliced, cut small, or coarsely
powdered in order to facilitate the solvent penetration.
 Menstruum
Always water (cold or boiling).
Time
Determined according to the amount of drug constituents to be extracted and
the ease or difficulty with which the water penetrate the drug.
Examples
Teas- Senna infusion- Infusion of senega
This method is used for those drugs are soft in nature. In this process, drug is
cut to suitable size and menstruum is added in teapot or infusion pot for the
stated period, usually 15 minutes with occasional stirring and finally filtering
off. Coffee pot or tea pot is the simplest form of apparatus used for
preparing infusion. The drug is placed at the bottom of the pot. Menstruum is
added and is well stirred. Menstruum penetrate the soft tissue of plant &
diffuses the active constituents in to menstruum. After the specified time content
is strained, marc is not pressed and filtered. The filtrate used as it is without
dilution. Infusion processes are two types: Fresh infusion and Concentrated
infusion.
PREPARATION
FRESH (DILUTE) INFUSION
▪The simplest of all methods of extraction
▪A definite weight of the crude drug in a certain state of subdivision (cut small,
powdered…) is prepared
▪The calculated amount of hot or boiling menstrum (usually water) is added to the
crude drug
▪Soak for a definite time
▪During the period of infusion, the heat should be retained in the container and the
content should be stirred
▪After the time of infusion, the liquid is poured off or strained
▪Do not press or squeeze the marc otherwise colloidal cell contents may be forced out
giving a cloudy infusion
▪Such fresh infusion should be used within 12 hours
CONCENTRATED (STOCK) INFUSION
▪To avoid rapid decomposition to which the fresh (dilute) infusions
are subjected.
▪These preparations are not made by the concentration of the
dilute infusion by evaporation, since thermal treatment will result in
loss of the volatile principles.
▪Concentrated infusions prepared with alcoholic menstrum or
contain alcohol as a preservative.
▪Concentrated infusion are not intended to be dispensed in the
concentrated state, but upon use, are diluted with at least seven
times their volume of water
▪Example: conc infusion of Quassia, diluted infusion of Gentian etc
GENERAL NOTES
▪The drug is usually coarsely ground. Very fine powders should be
avoided due to difficulty of separation from the infusion.
▪Where no specific directions are given, the following general
formula and procedure should be used : 50 gm Drug in 1000 ml
boiling distilled water (moisten 50 gm drug with 50 ml of cold
water and allow to stand for 15 minutes. Then, add boiling water
to make 1000 ml infusion).
▪Infusions of readily soluble active principles are prepared by
maceration in water cold.
GENERAL NOTES
Hot water extract the desired constituents more quickly than cold
but has the disadvantages of:
1- extracting inert materials that may precipitate upon cooling.
2- causing volatilization or destruction of certain principles.
3- coagulation of albuminous matters within the drug cell and
thereby inhibit the extraction.
DECOCTION
Definition:
- Solutions of the water soluble constituents of plant drugs
prepared by boiling the drug with water.
For extraction of drugs with water soluble and non- volatile
constituents, and drugs of hard and woody nature.
Should be freshly prepared.
Previously sliced drug barks or wood (5 parts) is boiled with water
(100 or 120 parts) in a vessel of enameled iron or earthenware for
a definite length of time (15 min.) counting from when the liquid
starts to boil with occasional stirring.
To obtain highly concentrated decoction, boiling is continued until the
liquid reduced to a certain volume.
Allow to cool to about 40ºC, press the marc and mix the resulting
liquid to the decoction.
At the end of decoction time, decoction is strained through fine muslin
or flannel according to the nature of marc. Then, sufficient water is
passed through the strainer to produce a definite volume.
Example: Cinchona bark or wood )‫( (خشب الكينا‬contains quinine)
Uses: treatment of fever, malaria and as an appetite Stimulant. Also
used in anemia, indigestion, gastrointestinal disorders, general fatigue.
COMPARISON BETWEEN INFUSION AND
DECOCTION
Item Infusion Decoction
1- Plant Soft structure (ex. Senna Hard woody structure (ex.
leaves) Cinchona bark)
2- Menstrum Boiling or cold water Boiling water
3- Procedure Infusing the drug with cold or Boiling the drug with water
hot water
4- Time Calculated as soon as water is Calculated as soon as the
added to drug water begins to boil
5- Adjustment of final No adjustment Adjustment is necessary
volume
6- Apparatus Infusion earthenware pot Any covered apparatus
7- Storage Used fresh within 12 hours Used fresh and when stored
in refrigerator used within few
days
DIGESTION
This process is a modified maceration in which extraction of drug is carried out
at a higher temperature at which the active ingredients are not adversely
affected. Use of higher temperature provides for enhanced solvent action of
menstruum. If the menstruum is readily volatilized at the temperature
employed, a reflux condenser is attached to the vessel so that the solvent may
get condensed, recovered and returned to the container. This process is
applicable to thermostatic one. It is also known as accelerated maceration.
Not applicable to volatile menstruum Eg:- gum, resin…..