Suppositories:
Definition of
suppositories:
The British Pharmacopoeia (BP) defines
as Suppositories are solid, single-dose preparations. The shape, volume and
consistency of suppositories is suitable for rectal administration.
OR
It is a solid dosage form meant to be inserted
into the body cavity like rectum urethra vagina where they melt or soften to
release the drugs and produce their local or systemic effect.
Explanation:
They contain one or more active substances
dispersed or dissolved in a suitable basis which may be soluble or dispersible
in water or may melt at body temperature. Excipients such as diluents,
adsorbents, surface-active agents, lubricants, antimicrobial preservatives, and
coloring matter, authorized by the competent authority, may be added if
necessary.
Advantages:
The main advantages of
suppositories are given as
•
They can be used to
exert a local effect on the rectal mucosa (e.g. anesthetic etc.)
•
They can be used to
promote evacuation of the bowel
•
If a particular drug
causes irritation of the gastrointestinal tract this can be avoided by rectal
administration
•
They can be used for
patients who are unconscious, fitting or vomiting, etc.
•
Systemic absorption can
be achieved by rectal delivery and has the added advantage of avoiding the
first-pass metabolism by the liver.
•
Drugs having bad odor
and taste can be used in the suppository.
Disadvantages:
The main disadvantages of suppositories are given as
•
They may be unacceptable to certain patients/ culture.
•
They may be difficult to self-administer by arthritic
or physically compromised patients. They have unpredictable and variable
absorption in vivo.
•
The manufacturing process is more difficult as
compared to other formulation.
•
The most important problem is storage conditions
because it is stored at low temperature 1O TO 20 centigrade. Other than gases
get liquefied.
• Leakage problem is also the most critical problem
along with suppository after introducing in body cavity at elevated
temperature.
Types of suppositories
Following are the main
types of suppositories
1) Rectal suppositories
·
It is inserted in the
rectum.
·
The weight of The suppository used in children is about 1 gm.
·
The shape of the suppository
in rectal is torpedo shape.
·
The length is about 3
cm.
2) Urethral suppository:
• The weight of this type of suppository is about
2 gm and 60 to 75 mm long in female.
• Those intended for male weight 4 gm each and 100
to 150 mm long.
• Its available in pencil shape.
3) Vaginal suppository:
•
It’s in the oviform shape.
•
It’s about 3 to 5 gm in weight.
•
It’s used for the treatment of infection in females.
•
It contains the combination of polyethylene glycol of different
molecular weight and suppository basis.
4) Nasal suppository:
•
These suppositories are meant for the introduction into nasal
cavity.
•
It’s about 1 gm. in weight.
Formulation of suppository:
There are many types of the basis used in suppository formulation but
the important basis is given as;
1) Water dispersible basis.
2) Water-soluble basis.
•
Glycerol gelatin basis.
•
Polyethylene glycol.
3) Lipophilic basis.
·
Cocoa butter.
·
Antioxidant basis.
·
Emulsifying agent.
·
Harding agent.
·
Preservatives.
·
Thickens agent.
·
Plasticizer.
Storage condition:
·
It's stored at 10 to 15
degree c.
·
Used in airtight
container.
·
The suppository and
pessaries with cocoa butter can be stored upto 30 degrees centigrade.
·
The suppositories with
glycerol gelatin stored at 35-degree centigrade
Pessaries:
Pessaries are a type of suppository intended for
vaginal use. The larger size molds are usually used in the preparation of peccaries,
such as 4g and 8g mounds. Peccaries are used almost exclusively for local
medication, the exception being prostaglandin pessaries that do exert a
systemic effect.
Ingredient of pessaries:
Common ingredients for inclusion in pessaries
for local action include:
* Antiseptics
* Contraceptive agents
* Local anesthetics
* Various therapeutic agents to treat
trichomonas, bacterial and monilial infections.
Definition
of pessaries:
The British Pharmacopoeia (BP) definition is as
follows:
Pessaries are solid, single-dose preparations.
They have various shapes, usually ovoid, with a volume and consistency suitable
for insertion into the vagina. They contain one or more active substances
dispersed or dissolved in a suitable basis that may be soluble or dispersible
in water or may melt at body temperature. Excipients such as diluents,
adsorbents, surface-active agents, lubricants, antimicrobial preservatives, and coloring
matter authorized by the competent authority may be added, if necessary.
Principle
of the suppository and pessaries preparation:
General principles of the suppository and pessaries
preparation
The methods used in the preparation of pessaries
are the same as those for suppositories. In this chapter, points relating to
suppositories can also apply to pessaries. For further details on a suppository
and pessaries bases, see Chapter 5 (page 80). The preparation of suppositories
invariably involves some wastage and therefore it is recommended that
calculations are made for excess. For example, if you are required to dispense
six suppositories, to include a suitable excess calculation for 10.
Suppository mold calibration:
Suppository molds are calibrated in terms of the weight of Theobroma Oil BP each will contain. Typical sizes are 1g, 2g, or 4g. Because the molds are filled volumetrically, the use of a base other than Theobroma Oil BP will require recalibration of the molds. Many synthetic fats have been formulated to match the specific gravity of Theobroma Oil BP and therefore the mold sizing will be the same and not require recalibration. However, this is not the case for all synthetic bases. To recalibrate a suppository mold, the compounder needs to prepare a number (e.g. five) of (perfectly formed) suppositories containing only the base. These can then be weighed and the total weight divided by the number of suppositories present to find the mold calibration.
General methods for suppository preparation:
1) Most molds prepare six suppositories, but it
is necessary to calculate to include an excess (usually a multiple of
10).
2) Choose a suppository mold to provide the
suppositories of the required size (usually a 1g size). Check that the two halve
soft molds are matched (numbers are etched on the sides).
3) Check that the mold is clean and assemble
the mold but do not over-tighten the screw.
4) For some suppository bases it is necessary to
lubricate the mold (e.g. use Liquid Paraffin BP), but this is not required
when using Hard Fat BP.
5) If the suppository is to contain insoluble,
coarse powders these must be ground down in a glass mortar before
incorporation.
6) It is important not to overheat the base,
which may change its physical characteristics. Find the melting point of the
base and heat it to about 5– 10C less than the melting point. (There should
still be some solid base present.) Hold the evaporating basin in the palm of
your hand and stir (do not use the thermometer to stir) to complete the melting
process.
7) Immiscible liquids and insoluble solids
should be incorporated into the fatty base by levigation (wet grinding). The
substance should be rubbed into the minimum quantity of molten base on a tile
using a spatula. The ‘shearing’ effect will not be obtained if too much base is
used, resulting in a gritty product.
8) The paste obtained in step 7 above should be
returned to the evaporating basin with the remainder of the base, stirring
constantly.
9) The molten mass should be poured into the
mold when it is just about to solidify. (This is usually judged by experience.
Look for a slight sheen on the surface of the mass, similar to asking to form a
custard as it cools.)
10) Pour the mass into the mold uniformly in
one movement.
11) Allow the mixture to overfill slightly but
not to run down the side soft the mold (if this happens, it is likely to be
due to the mixture still being too hot).
12) When the suppositories have contracted, but
before they have set completely, trim off the excess Hard Fat BP. This can
easily be achieved by rubbing the flat blade of the spatula over the top of the
mold.
13) After further cooling, when the
suppositories have set, loosen the screw, and tap once sharply on the bench.
Remove the suppositories carefully (avoid over handling or damaging the
suppositories with your nails).
14) Pack the required number of suppositories
individually in foil and place in an amber wide neck.
Packaging of
suppository:
An overview of the main considerations for the
packaging of suppositories and pessaries will be given here. Suppositories and
pessaries that have been manufactured in metal molds should be removed from the
mold carefully and individually wrapped in suitably sized pieces of aluminum
foil. Once wrapped, the suppositories can be placed in an ointment jar or
cardboard carton and labeled. Suppositories that have been manufactured in a
disposable mold are often dispensed to the patient in the mold. It is important
to ensure that the patient will be able to release each suppository from the
mold and that the label is placed on a suitable part of the mold. Sometimes,
it will be necessary to remove the suppositories from the disposable mold and
wrap and package as for those prepared in metal mounds
Discard dates in practical terms it is suggested
that an expiry date of three months is given to suppositories and pessaries in
the absence of any official guidance.
Remember that because patients frequently misunderstand
the term of ‘expiry’ it is suggested that a preferred method of indicating
shelf-life on the label of extemporaneously compounded products is to apply the the term ‘Discard after’ or ‘Do not use after’ followed by a definite date and/or
time. Further guidance on expiry dates to pharmaceutical preparations.
Labeling:
An overview of the main considerations for the labeling
of suppositories and pessaries will be given here. In addition to the standard
requirements for the labeling of extemporaneous preparations, the following
points need to be taken into consideration:
·
‘For rectal use
only’–This warning must be added to the label of any suppositories.
·
‘For vaginal use only’ –
This warning must be added to the label of any pessaries.
·
‘Store below 15C’ – This warning must be added to the label of all suppositories and pessaries.
References:
• Pharmaceutical compounding and dispensing 2nd
edition
• John F Marriott’s, Keith A Wilson, Christopher
A Langley and Dawn Belcher
• Chapter 11 suppository and pessaries page 183 to
196.
• Slide share written by Manoj Kumar.
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