Preparation of Suppositories - Pharmaceutics - I B. Pharma 1st Semester

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Preparation of Suppositories

Contents

• Methods
of preparation of suppositories

• Packaging
and storing of suppositories

• Quality control tests for
suppositories

Learning objectives

At the end of this lecture, student will be
able to:

• List
the methods of suppositories preparation

• Discuss
methods of suppositories preparation

• Discuss
packaging, storage conditions

•
Explain the quality control test for
suppositories

Methods of preparation of suppositories

Four
methods are used in preparing suppositories –

1. Hand moulding [Cold Hand Shaping]

2. Compression moulding

3. Pour moulding (Fusion method)

4. Automatic moulding machine

Hand
moulding [Cold Hand Shaping]

• Drug is triturated in a mortar into
fine powder

• Cocoa butter is grated into small
particles

• Drug is mixed with small portion of
cocoa butter in a mortar

• One drop fixed vegetable oil is
added to give plasticity to the mass

• Remainder
of the cocoa butter is added by geometric dilution and triturated with pressure

• Heat
generated by trituration results in a plastic mass, which is cohesive and ready
to roll

•
The mass is scrapped from the mortar with a
spatula and rolled into a ball

•
An ointment tile is taken, dusted lightly with
starch powder, ball is placed on it, rolled with a flat faced spatula to form a
cylinder

•
The cylinder is cut into desired number of
pieces with a sharp blade

•
One end of a suppository is held firmly with a
finger and the other end is tapered with the spatula to give the shape of
suppository

Compression
Moulding

• Drug is powdered and mixed with grated
cocoa butter

• The mixture is filled into a chilled
cylinder and is pressed within the cylinder by a piston until a pressure is
felt

•
Then
the suppositories are expelled from the cylinder

Pour
moulding (Fusion method)

• This is the main method of preparing
suppositories.

• Drug is powdered in a mortar.

• Carefully grated cocoa butter is
taken into a china dish and heated in a water bath.

• When 2/3rd portion is melted the
china dish is taken out of the heat source.

• The
rest of the mass is melted by stirring with a glass rod.

• [If cocoa butter is heated to clear liquid
then unstable α and γ – crystals will form and the suppositories will

remain in melted
state at room temperature.]

• Drug
is added into the beaker and stirred thoroughly to mix with the “creamy” base.

• The
“creamy” melted base is then poured into previously lubricated mould.

• The
mould is allowed to congeal, then placed in the refrigerator for 30 minutes to
harden (forms stable β-crystal after refrigeration).

• Mould
is taken out from the refrigerator and surface is trimmed off.

• The
mould is opened and the suppositories are expelled out of the mould by gentle
pressure with the finger.

Automatic
moulding machine

Two types
of moulding machines are available:

a) rotary moulding machine

b) straight-line moulding machine

Manufacturing
cycles in rotary moulding machine:

• Prepared mass is filled into a
filling hopper where it is continuously mixed and maintained at constant
temperature.

• The suppository moulds are
lubricated by brushing or spraying lubricant solution.

• The molten mass is filled in the
moulds to a slight excess.

• The mass is cooled to solidify and
the excess material is scrapped off and collected for re-use.

• In the ejecting section, the mould
is opened and the suppositories are pushed out by steel rods.

•
The
mould is closed, and then moved to the first step of the cycle.

q The output of a typical rotary
machine ranges from 3500 to 6000 suppositories an hour.

q Here the cycle is similar to rotary
moulding machine but the individual moulds are carried on a track through a
cooling tunnel, where scrape-off and ejection occur.

Suppositories filling machine

Suppository shapes

Packaging
requirements

q Bulk storage: The individually
wrapped suppositories are packaged in slide, folding, or set-up boxes.

q Suppositories containing hygroscopic
or volatile material are packed in glass or plastic containers.

q Suppositories are not individually
over-wrapped.

q They are placed in sectioned
card-board boxes or plastic containers to hold 6 or 12 suppositories.

In-package
moulding method

Advantage:

• If the suppository melts at higher
storage temperature their shapes are retained which can be used just by
chilling again

Suppositories

Storage of suppositories

q Suppository
should be protected from heat, preferably stored in the refrigerator

Quality
control tests for suppositories

1. Visual Inspection test

2. Disintegration test

3. Uniformity of mass

4. Uniformity of drug content

5. Melting Point determination Test

6. Liquefaction / softening time test

7. Fragile/ breaking test

Summary

Four methods are used in preparing
suppositories –