Suppositories are solid dosage form
containing medicament intended for insertion into the body cavities other than
mouth. They may be inserted into rectum, vagina, ear and nose. After insertion
the suppositories may melt at body temperature or dissolve in the cavity fluids
and release the medicament.
Suppositories are used to produce:
1. Local action: Ex- Antiseptic
astringent and local anaesthetic effect.
2. Systemic action: Ex- Analgesic,
anti-spasmodic, sedative effect.
3. To evacuate the bowels
1. The drugs which cannot be taken
orally (which irritates GIT or which produces vomiting) such drugs can be
administered in the form of suppositories.
2. Suppositories can be administered
to a person who is un-able to swallow the drug. (When he is un-conscious).
3. The drug which is decomposed or
inactivated by gastric HCL or by the enzymes present in the stomach, such drugs
can be administered in the form of suppositories.
4. These can be easily administered to
children and the old person.
5. Drugs sensitive to acidic PH
can be administered safely.
6. When-ever local effect is required.
It can be placed directly at the site of action.
7. Drugs are more rapidly absorbed in
rectal mucosa without ionization.
8. Non-sealing and biter drugs can be
given in this from without difficulties.
1. Irritant drugs cannot be
administered in the form of suppositories.
2. Large quantities cannot be
administered in the form of suppositories.
Different types of suppositories:
The suppositories are marketed in
different sizes and shapes for use in the different body cavities. The common
Rectal suppositories: They are meant for introduction into
the rectum. Weight – 1 to 2 grams, Shape
Vaginal suppositories or pessaries: They are
meant for introduction into the vagina.
Weight – 4-8grams, Shape- either cone, rod and
wedge in shape
Urethral suppositories: They are meant for introduction into
the urethra. Weight – 1grams, Length
– 8 cm, Shape – pencil shaped
pointed at one end then cylindrical.
4. Nasal suppositories: They are meant for introduction in the nasal cavity. Weight –
1gram, Length – 9-10cms, Shape – thin cylindrical in shape.
They are meant for introduction onto the ear,
Weight – 1 gram, Shape – Thin and
cylindrical shape they are very merely used.
Containers for suppositories:
Suppositories are usually dispensed in
shallow, partitioned boxes which hold the suppositories in n upright position
and do not allow them to come in contact with each other.
Suppositories containing volatile
substances must be dispensed in tightly closed glass containers.
All suppositories are required to
retain the shape at room temperature. It is therefore necessary that
suppositories be stored at 10-250C
Suppository bases are used to prepare
suppositories, so that they can retain its shape and firmness during storage
Ideal properties suppositories bases:
1. Melt at body temperature and
dissolve or disperse at body fluids.
2. Non-toxic, non-irritant and
3. Compatible with large variety of
4. Stable on storage.
5. It should be easily moulded.
6. It should release medicament.
7. It should not adhere to the mould
by pouring or by cool compression.
8. It should be stable if it is heated
above its melting point.
9. It should keep its shape while
10. These have wetting and emulsifying
11. It is vegetable or animal fat,
following standard must comply.
Acid values less than – 3
Iodine value less than – 7
Saponification value – 200-275
12. It has a wetting and emulsifying
13. Melting and solidification points
should be closed.
Classification of suppositories base with examples:
These are classified into three types
1. Oily bases:
Ex – cocoa butter: It is also known as theobroma oil. It is obtained from crushed and
roasted seeds of theobroma cocoa.
1. Melting point lies between 30-350C.
2. It is composed of mixture of
glyceryl esters of stearic, palmitic, oleic and other fatty acids.
3. It has smell and taste like
4. It is a yellowish white solid.
5. Cocoa butter melts at body
temperature and releases them.
6. It shows the phenomena of
polymorphism, when melted and cooled,
solidifies into different crystalline form:
α form: It melts at 240C, obtained by sudden cooling of cocoa butter at 90C.
β1 form: It crystallizes
out from liquefied cocoa butter by stirring at 18-230C. Its melting point lies between 28-310C.
β-form: It changes slowly in form which melts
between 34 – 350 C.
Its melting point is 180C
is obtained by pouring a cooled cocoa butter 20C into a container, cooled at deep freeze temperature.
1. Solid at even high room temperature
but melt quickly at body temperature.
2. It is very stable.
3. It is chemically inert.
4. It is non-reactive.
5. Miscible with many ingredients.
1. Over heating changes its physical
characters because of polymorphism. Each has different melting points
α form -24OC
β1 form -28O – 31OC
β form -34O– 35OC
ϒ form -18OC
β1 changes slowly into stable β form.
2. Melt in warm weather.
3. Adherence to mould.
4. It cans rancidity.
5. Deterioration during storage due to
6. Poor water absorbing base.
7. It is costly.
8. Leakage of melted base.
9. It melting is lowered by
overheating and by incorporation of substances like camphor, phenol.
Hydrogenated oil: It
is used as a substitute for theobroma oil. It is obtained by hydrogenation of
various vegetable oils, such as Arachis oil, cotton seed oil, coconut oil, palm
oil etc. It is used as a substitute for theobroma oil.
These have certain advantages over
1. Resistant to oxidation.
2. Good emulsifying and water
3. Lubrication of mould is not
2. Water soluble or water miscible base:
Glycerol-gelatin base: It is also known
as glycerine suppositories. It is a mixture of glycerine and water which is
made stiff by the addition of gelatine. Suppositories prepared from this base
are translucent gelatinous solids. This base is hydrophilic in nature slowly dissolves
in the aqueous secretions and release the medicaments slowly and continuously.
This base may be used to prepare all types of suppositories but it is
particularly used as a base in vaginal suppositories. These suppositories if
required to be stored, must have preservatives like methyl paraben and propyl
To avoid incompatibility reactions
suitable type of gelatin is used two grades of gelatin are available.
1. Pharmagel A (Type A): It is acidic
in nature and used for acidic drugs. Its iso-electric point lies between 7 to 9.
2. Pharmagel B (Type B): It is
alkaline in nature and used for alkaline drugs. It iso-electric point lies
1. They are more difficult to prepare
2. They are hygroscopic therefore they
must be stored in well closed containers.
3. Gelatin is incompatible with many
drugs. Ex-Tannic acid, Fecl3.
4. They support bacterial and mould
Poly- ethylene glycol: These are known
as macrogols or carbo- waxes. They are widely used for preparing suppositories.
They are chemically stable and physiologically inert.
They do not support bacteria and mold
growth. Poly ethylene glycols are available in different physical forms.
1. Molecular weight 200-1000 is
2. Molecular weight higher than 1000
are was like solids.
1. These are non-irritant and
2. These absorb water and have
excellent solvent property.
3. Physical properties can be varied
by addition of high and low molecular weight polymer.
1. High solubility of PEG leads to
supersaturations which in turn makes crystals and fracture the product on
2. They are hygroscopic and hence
require special storage conditions to store them.
3. They are incompatible with certain
drugs like tannins and phenol etc.
Soap glycerine base: It is mixture of
gelatin and sodium stearate. It contains 95% of glycerine. The soap is
generally produced by interaction of stearic acid and Na2CO3.
Glycerin-90g, NaCO3 -4.5g, Stearic acid-7.5g
It is very hygroscopic
3. Emulsifying bases:
It contains mono-glycerides as
emulsifying agent. It forms w/o type emulsion. It can absorb very easily.
Massa esterinum: It is mixture of
mono, di, tri glycerides of saturated fatty acids. It is a white brittle solid.
It melt at 33-35OC.
Witepsol: It consists of glyceryl esters, mainly
of lauric acid, to which a very small amount of glyceryl mono-sterate is added
to improve its water absorbing capacity.
1. Lubrication of mould is not
2. Non-irritant and resistant to
3. Over-heating does not affect
4. These solidify rapidly
5. Their emulsifying and water
absorbing capacities are good.
1. They should not be cooled in refrigerator
because they become brittle.
2. They are less viscous on melting
which results in sedimentation of other substances.
The quantity of the drug which
displaces one part of the base is known as displacement value.
The volume of suppositories prepared
from a particular mould is uniform.
Their weights will vary when compare
to the plain suppositories.
It is due to the variation of the
medicament with the density of the base.
That means the weight of the
medicament may not displace the same volume, because of the variation in the
But the medicament displaces the same
volume of the base.
To prepare an accurate suppository an
allowance (extra weight) may be given or the alteration in the density of the
mass due to the added medicaments.
It is calculate by applying
Ex– Iodoform – 0.9g, Cocoa butter base – 2.0g.
Make into suppositories send 8 Nos.
one to be inserted into rectum at bed time. Displacement value of lodoform is
Calculate 2 suppositories extra. The base
given is 2g so 2g weight suppositority mould is used.
Weight of cocoa butter for the suppository
Therefore weight of cocoa butter for
10 suppositories 2*10g =20g
Weight of iodoform for the suppository
Therefore of iodoform for 10
suppositories =0.9g *10=9g.
Displacement value of cocoa butter
Total amount of base – total amount of drug.
= 20-2.25 =17.75g
Formula for 10 iodoform -9.0g
Cocoa butter – 17.75g
Determination of displacement value:
Displacement value of a medicament can
be calculated as follows.
1. Prepare and weight 10 suppositories
containing theobroma oil or any other base =a grams
2. Prepare and weight 10 suppositories
containing 40% of medicament =b grams.
3. Calculate the amount of theobroma
oil present in the medicated suppository =60/100*b =c grams.
4. Calculate the amount of medicament
present in the medicated suppository =40/100*b=d grams.
5. Calculate the amount of theobroma
oil displayed by d grams of medicament. Let it be (a-c) grams
Displacement value of medicament= d
Displacement value of some drugs:
Chloral hydrate – 1.5
Hydro-cortisone – 1.5
Aminophylline – 1.5
Tannic acid – 1.0
Bismuth subgallate – 2.5
ZnO – 5.0
Different methods of Preparation of
can be prepared by following method:
I) Fusion method
I) Cold compression method
II) Hand moulding (Rolling Method)
1. Heat process:
I) Fusion method:
1. The suppository mould is thoroughly
washed and dried.
2. The inner surface of the mould
(cavities) is lubricated with liquid paraffin or any suitable lubricant.
3. Calculate the base required as per
displacement value of medicament.
4. Heat the dish over the water bath
or steam bath.
5. Take calculated amount of base
place on dish and is melted at 30-35Oc.
6. Remove the dish when 2/3 of the
7. Place the weighed quantity of
medicaments on a warmed tile. Over it pour the melted base.
8. Mix it thoroughly with a flexible
spatula and transfer the mixed mass to a dish and stir to from a homogenous mass.
9. Warm the dish over water bath for
few seconds so that mass becomes pourable.
10. Pour this melted mass into
cavities of mould kept over ice. Fill each cavity to overflowing to prevent the formation of hollow voids on
11. Precaution must be taken while
filling the cavities to stir continuously to ensure uniform distribution of medicament.
12. Mould is kept in a cool place or
over ice for 10-15 minutes.
13. The excess mass is scrapped off
with a knife.
14. The mould joint is then separated
and the suppositories are removed and packed. This method is useful for both
small and large scale method.
15. For a large scale method, pouring,
cooling and removal can be performed by machine.
2. Cold process:
Cold compression method:
This method does
not require heat and stirring so it is best suitable for thermolabile and
It is un-suitable
for glycerol-gelatin Suppositories.
In this method
mass is prepared by first mixing the powered medicament with an equal amount of
cocoa butter in a motor.
weight) is made for un-avoidable wastage.
It is prepared by
using machine. This machine contains cylinder pistons, narrow opening, mould
and stop plate.
remaining quantity of grated cocoa butter gradually.
The mixture is
then transferred to the cylinder of the machine and pressure is applied.
forced the material from cylinder to mould through narrow opening.
are formed at mould.
The pressure is
further applied stop plate F is removed and the finished suppositories are
The operation is
repeated for the next set of suppositories.
II) Hand moulding (Rolling Method):
It is ancient method of preparing the
suppositories. The suppository base is rolled and then desired shape is given
with the hand. This method I not used nowadays.
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