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

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 -

1.       Hand moulding [Cold Hand Shaping]

2.       Compression moulding

3.       Pour moulding (Fusion method)

4.       Automatic moulding machine

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