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1. Pharmaceutical Quality management- Theory
By
Ms. Rabia Khokhar
Ph.D. (Scholar), M.Phil., R.Ph.
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2. ALKALOID
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3. • Introduction
• Preparation of drug for assay- Weighing for assay
• Extraction of drugs
a) Maceration
b) Percolation
c) Continuous extraction
• Purification of Alkaloids
• Determination of alkaloids
3

4. We are the basic
nitrogen containing
compounds with definite
pharmacological activity.
We are the basic
carbonyl group
containing compounds
with definite
pharmacological activity.
We are the basic carbon
containing compounds
with definite
pharmacological activity.
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5.  ASSAY
 The determination of the activity, potency, strength, etc. of a substance, either on an
absolute basis or in comparison with that of a standard preparation. OR
Qualitative or quantitative analysis of a substance, especially of a drug, to determine its
components. OR
 Determination of the amount of a particular constituent of a mixture, or of the potency of
a drug.
 So, the assay of the drugs containing alkaloids is called
―Alkaloidal Drug Assay.
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6. ALKALOIDS
Alkaloids are the organic compounds normally with basic chemical properties and usually containing
at least one nitrogen atom in a heterocyclic ring,
It occurs chiefly in many vascular plants and some fungi; having marked physiological effects on
humans or animals.
 Many alkaloids, such as nicotine, quinine, cocaine, and morphine, are known for their poisonous or
medicinal attributes.
Alkaloids are slightly or very slightly soluble in water.
Alkaloids are soluble in certain organic solvents immiscible with water e.g. chloroform.
Salts of alkaloids are soluble in water but almost insoluble in organic solvents.
The process of assay is carried out by treating the drug with a solvent immiscible with water in the
presence of excess of alkali that liberates the alkaloid.
 The free alkaloid is dissolved by the immiscible solvent from which it is removed by means of excess of dilute acid.
 The acid solution is then extracted with an immiscible solvent in the presence of alkali.
 The immiscible solvent is then evaporated to obtain the alkaloid which is either weighed or determined volumetrically.
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8. 8
Stimulant
Anti-hypertensive
Motion sickness

9.  Grind the drug to be extracted to a powder of fineness grade.
a. Weighing of bulky crude drugs:
In weighing bulky crude drugs for the assay, accuracy to within 10 mg for
quantities of 5 gm and over is sufficient.
b. Portions of soft extracts or ointments:
These may be weighed on a tarred piece of wax paper and transferred to the
vessel containing the solvent for extraction.
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10. The alkaloidal content of alkaloid-bearing drugs is usually extracted
by one of the following methods.
1. Maceration
2. Percolation
3. Continuous Extraction
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11. Introduction
 The term maceration comes from the Latin ‗macerare‘ which means ‗to soak‘.
 It is a process in which the properly crushed drug is permitted to soak in the menstrum until the
cellular structure is softened and penetrated by the menstrum, usually for 2-14 days
 By this method, nearly all the soluble contents are dissolved in the menstrum.
 Menstrum: A solvent, especially one used in extracting compounds from plant and animal
tissues and preparing drugs.
 Maceration is different from water based infusions and decoctions in following respects:
o The menstrum is usually alcohol.
o The herb remains in the menstruum for a longer period of time.
o The process is conducted at ordinary temperature.
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12. Procedure
METHOD 1
1. The drug is placed in a wide mouth container containing certain menstruum.
(The vessel is closed tightly to prevent the loss of menstruum.)
2. The contents are shaken/agitated repeated (preferably on daily basis) for a period of 2 to 14
days.
(The agitation allows the repeated flow of fresh menstrum over the entire surface area
of soaked comminuted drug.)
3. After the specific time, the liquid is drained from the marc. The marc is then pressed to
retrieve more of the menstruum.
4. The expressed liquid is mixed with the strained liquid and the mixture is left to stand until it
is clear
5. Finally, it is filtered.
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14. METHOD 2
1. Place the drug in a porous cloth bag that is tied and suspended in the upper portion of
menstruum. (Just like a teabag).
(As the soluble contents dissolve in the menstruum, they tend to settle to the bottom due
to density difference)
2. The extractive is separated from the marc by expressing the bag of drug and washing it with
additional menstruum.
3. The menstruum is then filtered.
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15. Specifications for Maceration
 Maceration is usually conducted at a temperature between 15 to 20 ° C.
 Duration is from minimum 2 days to maximum 14 days.
 Wide mouth vessel is used.
 Mouth of vessel is stoppered tightly.
 Contents are agitated repeatedly.
Examples:
Benzoin
Aloe
Tolu
Aloe
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16. Introduction
 The term percolation is derived from the Latin ‗per‘ meaning ‗through‘ and ‗colare‘ meaning
‗to strain‘.
 Therefore, it is a process in which a comminuted drug is extracted of its soluble constituents by
a slow passage of a suitable solvent through a column of the drug.
 According to USP :
“Percolation consists in subjecting a comminuted substance or a mixture of substances
contained in a vessel called a percolator, to the solvent action of a liquid termed as
menstruum in such a manner that the liquid shall extract the soluble constituents and pass
from the percolator.”
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18. Simple
Size reduction or comminution of drug
Imbibition or moistening of drug
Packing
Maceration
Percolation

19. Procedure
1. The comminuted drug is packed in a special extraction apparatus termed as percolator by
packing the outlet with some porous material e.g. cotton.
2. Saturate the drug with specified solvent and allow standing for 5 minutes- 4 hours
3. Add some ammonia sufficient to make the mixture distinctly alkaline and mix thoroughly
with drug.
(From this percolator, the suitable solvent (menstruum) is passed through slowly which
dissolves the soluble constituents of the comminuted drug.)
4. Allow the drug to macerate for about 10 to 12 hours. (up till 24 hrs)
5. That menstruum is now called ―Percolate‖ and is collected from the bottom of percolator
until the drug is completely exhausted of its alkaloidal content.
(The flow of the menstruum is generally downwards due to gravity.)
 In some specialized and more sophisticated percolation apparatus, additional pressure is
exerted on the column with positive air pressure at the inlet and suction at the outlet.
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How will we
know ???

20. Determination of the completeness of extraction of alkaloid
a. Take about 4 ml of the last percolate.
b. Evaporate it to dryness.
c. Dissolve the residue in 0.5 ml of 0.5 N acid.
d. Add a drop of mercuric iodide (Valser‘s Reagent)
e. A slight turbidity is produced 
Alkaloid is present
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21.  Percolators employed on large scale industrial preparations are generally made
up of stainless steel or glass lined metal vessels and vary greatly in size &
operation.
 For example: percolators used to extract from leaves may be 6 to 8 feet in
diameter and 12 to 18 feet high.
 Percolators used on small scale are usually made up of glass.
 Shapes
Cylindrical
Roundish
Conical
Funnel shaped
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23. OPEN PERCOLATOR
 used when the menstruum is
water or dilute alcohol.
 cheap and easy to handle.
CLOSED PERCOLATOR
 used when the menstruum is
volatile e.g. alcohol, ether etc.

24. “Percolators used at Industrial scale”
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26.  This continuous extraction process combines the two normal operations of
simple extraction i.e. extraction and evaporation
 That is, immediately after contact with drug, the solution is evaporated and
vapors taken to a condenser, where the condensed liquid is returned to drug to
continue extraction
 Thus, with the help of temperature, smaller volume of solvent may be used and
the process of extraction may be called continuous extraction.

27.  Used in cases where:
 The penetration of the menstruum into the cellular tissues is very slow
 The quantity of menstruum is very less.
 The solute is NOT readily soluble into the solvent
 Apparatus used: Soxhlet extractor
 In this case, small volume of hot menstruum is passed over the drug time and
again to dissolve out the active constituents until the drug is exhausted. This
process is known as Soxhlation.
 IMPORTANT  the volume of solvent is used again and again with the
help of special apparatus OR solvent recycling

28. Procedure
1. Moisten the drug with a specified solvent.
2. Allow to stand for 5 mins.
3. Make the mixture alkaline using ammonia and mix thoroughly.
4. Allow the drug to macerate for 6-12 hrs.
5. Then pack the drug in the thimble and cover it with a pledge of cotton.
6. Take the thimble and insert it into a suitable extractor e.g. Soxhlet extractor.
7. Add sufficient quantity of solvent and extract the drug.
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29.  Soxhlet apparatus, consists of three parts :
 a flask in which the menstruum is boiled
 an extraction chamber in which drug is filled, is fitted with a
side tube and a siphon
 a condenser
 Vapors pass through side tube, enters condenser where they are
condensed, fall back on the packed drug in the extraction chamber,
percolates and extracts out the active constituents
 As the volume of menstruum in the extractor increases, volume in
siphon also increases, till it falls back into the flask

30.  Further heating vaporizes the Menstruum & Active ingredient remain behind in
the flask.
 Filling and emptying of extractor goes on continuously and the process is
repeated for 14-15 times through the drug and active constituents are collected
in the flask.
Disadvantage: NOT suitable for thermolabile constituents

31. 31
Flask
Sipho
n
Condense
r
Extraction
Chamber
SOXHLET
APPARATUS

32.  The alkaloidal solution obtained by any of the extraction methods is usually contaminated with other extractives
which interfere with the quantitative determination of alkaloids.
 For effective purification, remove the alkaloids from the immiscible solvent by shaking out with an acid.
 Then make the acidic solution alkaline with an alkali hydroxide and extract with an immiscible solvent.
 The volume & strength of the acid vary case to case. However total volume should be as small as possible.
 Shake the combined acid extracts with one or more 10 ml portions of the appropriate immiscible solvent until the acid
solution is clear. Then wash the immiscible solvent
 extracts with one or more 5 ml portion of water acidified with HCl or H 2 SO 4 and add these washings to the acid
solution.
 Then make the acid solution alkaline with ammonia and extract it with some immiscible solvent.
 Repeat the operation as long as any alkaloid is extracted by the immiscible solvent.
 The completeness of the extraction can be tested by mercuric iodide TS.
 In all assays, continues the extraction until 0.5 ml of the last acid washing shows a very slight turbidity on the addition
of a drop of mercuric iodide.
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33.  Evaporate the solution of the purified alkaloids in the immiscible solvent to dryness on a steam
bath or with a current of air.
 Soften the alkaloidal residue by addition of about 1 ml of the neutralized alcohol or ether.
 Add an accurately measured volume of standard acid.
 Warm the mixture gently.
 Dissolve the alkaloidal residue in chloroform and add standard acid of higher normality.
 Remove the chloroform completely by evaporation.
 The add water (q.s) to make the volume of mixture at least 25 ml.
 Titrate the excess of the acid with standard alkali.
 Dry the alkaloidal residue at 105 °C to a constant weight.
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34. 1) Mayer’s Test
2) Dragendroff’s Test
3) Wagner’s Test
4) Hagger’s Test
5) Tannic Acid Test:
6) Melting Range Test:
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35. Estimation of alkaloids
 Following tests are used to detect the presence of alkaloids:
1) Mayer’s Test: It gives white or yellow ppt except with alkaloids of purine group
2) Dragendroff’s Test: Orange colour ppt formed.
3) Wagner’s Test: Brown or reddish brown ppt.
4) Hagger’s Test: Characteristics crystalline ppt.
5) Tannic Acid Test: Freshly prepared tannic acid solution gives ppt which is
insoluble in dilute acid.
6) Melting Range Test: Every alkaloid has specific melting range like Atropine has
114-118 o C.
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