An Overview Of Suppositories

Suppositories are manufactured to insert into the body cavities or the orifices where their melting at room temperature and dissolution occur, and they exert localised action on the body. The action of suppositories depends on the nature of the drug, its concentration, and the rate of absorption in the body. The systematic action of analgesics, antispasmodics, sedatives, tranquillisers and antibacterial agents plays an important role. 

Characteristics of suppositories:

• Easy to melt at room temperatures
• Can be easily inserted into body cavities, including the rectum, vagina, urethra, nose, and ear
• They are known to melt drugs for their administration
• They have a systematic effect

Types of suppositories

Suppositories are classified as:

• Rectal suppositories: 
• They are made for adults and children
• They are shaped like a torpedo
• They possess about 2 gm and 1 gm of weight for adults and children, respectively
• They are inserted into the rectal cavity
• They are about 3 cm in length

Physiologic factors that affect drug absorption from rectal suppositories: 

As we know, many factors cannot be administered orally in the body as they are affected by the digestive juices, and the enzymes present in the liver modify their therapeutic activity after absorption from the small intestine. The anorectal area is where most of the rectal drugs are administered. Release of the drug from the suppositories bases occurs because the drug melts. To avoid this melting, ephedrine sulphate and quinine hydrochloride are used. 

• Vaginal Suppositories:
• Vaginal suppositories are also called pessaries
• They are about 3-5 gm in weight
• They have globular, conical shapes
• Urethral Suppositories:
• They are also called bougies
• They have a pencil-like shape
• They are 2 gm in weight and about 75 mm in length
• Nasal Suppositories:
• They have another name, nasal bougies
• They are designed to insert into the nasal cavity
• Their preparation is done with a glycerogelatin base
• Ear cones:
• They are used rarely
• Ear cones are specially designed to insert into the ears
• In-ear cones as a nase Theobroma are used

Suppository bases

• Bases must have a solid form at room temperature
• It should possess a less irritating property
• They should be able to produce an inflamed sensation in body cavities like the vagina, urethra, etc
• It should be stable during storage conditions. Changes in colour, shape and 

odour must be adhered to

• They should be soft so that they can be handled easily
• It must be nonreactive with drugs and additives so that harmful reactions can be avoided
• It should have good emulsification properties
• The acidic acid value must lie between less than 0.2 and zero
•  It should have an iodine value of less than 7

1. Water-dispersible bases are the hydrophilic bases having a mixture of non-ionic

Surfactants. These are the chemically related mixture to polyethylene glycol. Methylcellulose is a cellulose derivative that comes under this category. 

Advantages

• Suitable for both water and oil-soluble drugs.
• They terminate the growth of microbes in the preparation.
• Their storage can take place at elevated temperatures.

Disadvantages-

• Their interaction takes place with a few drugs.  

Examples 

• Polyoxyethylene sorbitan fatty acid ester(TWEENS)
• Polyoxyethylene stearates(MYRIS)
• Water-soluble bases
• Glycero-gelatin

This occurs as a gel and is a mixture of gelatin, glycerol, and water.

Advantages: Strong and translucent

Disadvantage: It absorbs moisture and sometimes promotes the growth of microorganisms. 

• Polyethylene glycol

It is also called PASTONALS, PEG, macrogols or polyglycol. 

PEG can be solid or liquid. 

Advantages

• Thermostable
• Degradation or hydrolysation cannot take place
• Free to microbial growth
• After introduction into the body cavities, they cannot come out. They are chemically stable

Disadvantages

• Susceptible to rancidification
• It melts easily at high temperatures
• It cannot absorb a high quantity of water
• It can be leaked after introduction into the body

Advantages of suppositories

• On rectal mucosa, they exert a local effect
• Evacuation of the bowel is promoted
• It can be useful to unconscious patients during fitting
• They help avoid first-pass metabolism
• They are used for the systemic absorption of drugs
• It can be used by people who are suffering from nausea and vomiting
• People who cannot be administered post-op oral medication will be benefitted
• Infants and older adults are more suited to suppositories because of their ability to melt
• They are ideal for those drugs which are destroyed by portal circulation
• It can also be used to avoid the distastefulness of a few drugs

Disadvantages of suppositories: 

• They are not accepted by every patient; hence, their suitability depends on patient adaptability
• Suppositories promote evacuation of the bowel, which sometimes leads to incomplete absorption
• The problem of leakage is the most critical problem of suppositories after their introduction into body cavities at an elevated temperature
• Suppositories have a storage problem. The suitable temperature is about 20 degrees celsius. Below this temperature, the bases start to liquify

Conclusion

Through this article, we can conclude that suppositories are another way of administration of the drug. They have been proven ideal for administration in adults and infants, and methods include various olfactory areas and the rectum.