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Suppositories Introduction Suppositories are solid pharmaceutical dosage forms designed to be inserted into body orifices where they soften, melt, dissolve, or disperse to liberate the incorporated drug(s) that exert local or systemic effect.Such bases are divided into 2 major categories:

• Fatty bases; which are divided into natural fatty bases like theobroma oil (cocoa-butter) and synthetic fats (prepared from vegetable oils).Preparation of suppositories Displacement value and calculations Because the density of each medicament varies from that of the base, the weight of the base required to make a suppository will vary depending on the drug used.For example, bismuth subgallate suppositories are used as astringent in treating hemorrhoids
• Suppositories for systemic effect: Drugs are sufficiently absorbed to exert systemic effect.Active and inactive ingredients are dispersed in an inert matrix composed of solid bases.- Water-soluble and water miscible bases: For example, glycerol-gelatin suppositories which are a mixture of glycerol and water stiffened with gelatin.Theobroma oil has a major drawback of undergoing polymorphism when overheated, and should be stored at a cool place preferred at 4 ?C.A major disadvantage of glycerol-gelatin suppositories is osmosis which produces a laxative effect.Theobroma oil is obtained from the roasted seeds of theobroma cocoa.Gelatin is a natural protein obtained from collagenous tissue, such as skin and bones of animals.They can be classified according to the site of action into 2 major types:
• Suppositories for local effects: laxative and anti-hemorrhoidal suppositories.For example, Anti-asthmatics, anti-rheumatics and analgesics suppositories.

Suppositories
Introduction
Suppositories are solid pharmaceutical dosage forms designed to be
inserted into body orifices where they soften, melt, dissolve, or disperse to
liberate the incorporated drug(s) that exert local or systemic effect. They can
be classified according to the site of action into 2 major types:

• Suppositories for local effects: laxative and anti-hemorrhoidal
  suppositories. For example, bismuth subgallate suppositories are used
  as astringent in treating hemorrhoids


• Suppositories for systemic effect: Drugs are sufficiently absorbed to
  exert systemic effect. For example, Anti-asthmatics, anti-rheumatics
  and analgesics suppositories.
  Active and inactive ingredients are dispersed in an inert matrix composed of
  solid bases. Such bases are divided into 2 major categories:


• Fatty bases; which are divided into natural fatty bases like theobroma
  oil (cocoa-butter) and synthetic fats (prepared from vegetable oils).
  Theobroma oil is obtained from the roasted seeds of theobroma cocoa.
  Theobroma oil has a major drawback of undergoing polymorphism
  when overheated, and should be stored at a cool place preferred at 4 °C.


• Water-soluble and water miscible bases: For example, glycerol-gelatin
  suppositories which are a mixture of glycerol and water stiffened with
  gelatin. A major disadvantage of glycerol-gelatin suppositories is
  osmosis which produces a laxative effect. However, this laxative effect
  may be considered as a therapeutic goal to treat constipation. Gelatin is
  a natural protein obtained from collagenous tissue, such as skin and
  bones of animals.
  Preparation of suppositories
  Displacement value and calculations
  Because the density of each medicament varies from that of the base,
  the weight of the base required to make a suppository will vary depending
  on the drug used. When calculating the amount of the base required to make
  a suppository of certain medicament, the displacement value of a particular medicament must be taken into account. The “displacement value” of a drug
  is the number of parts by weight of drug that displaces 1 part by weight of
  the suppository base.
  Glycero-gelatin base has a density 1.2 times greater than theobroma
  oil which means that 1 g suppository mold will produce a 1 g theobroma oil
  suppository, but a 1.2 g glycero-gelatin suppository.
  Molding process
  Mixture of drug and suppository base in its liquid state is poured into
  molds and then cooled to congeal. At laboratory scale, the mold has either
  six or twelve cavities into which the molten mass is poured. Different sizes
  of cavities are available; 1 g, 2 g and 4 g sizes.
  Cavities are overfilled with molten mixture to prevent formation of
  recessed dips in the end of the suppository. Pouring of the molten base
  should be continuous to prevent layering of suppository (congealing of the
  melt into layers) which may result in breaking on handling.
  Mold cavities are usually lubricated prior to molding. The purpose of
  using a lubricant is to form a barrier between the mold and the mass, thus
  prevent sticking. This facilitates cleaning of the mold and removal of
  molded suppositories. A lubricant is a liquid which does not mix with the
  poured suppository.
  Molds are found in different shapes, giving suppositories designed to
  be easily inserted into the body orifice without causing over distension.
  Torpedo is a common shape for rectal suppositories.