Definition
Suppositories are solid dosage forms intended for insertion into body cavities, such as the rectum, vagina, or urethra, where they melt, soften, or dissolve to release the active pharmaceutical ingredient(s).
Suppositories are typically made from a base material that is either lipophilic (fat-soluble) or hydrophilic (water-soluble).
Illustration of Suppositories
Types of suppositories:
1) Rectal suppositories:
These are the most common type of suppositories and are intended for insertion into the rectum.
They are usually cone- or torpedo-shaped and are used for local or systemic drug delivery.
2) Vaginal suppositories (pessaries):
These suppositories are inserted into the vagina and used to treat local infections or to deliver hormones for contraceptive purposes.
They are usually oval or globular in shape.
3) Urethral suppositories:
These are less common and are intended for insertion into the male or female urethra.
They are typically used for local anaesthesia or the treatment of erectile dysfunction.
Advantages of suppositories:
1) Bypass first-pass metabolism:
Drugs administered via suppositories can avoid first-pass metabolism in the liver, which may improve bioavailability for certain drugs.
2) Alternative route for patients with difficulty swallowing:
Suppositories are useful for patients who have difficulty swallowing oral medications, such as young children, the elderly, or those with swallowing disorders.
3) Suitable for unconscious or nauseous patients:
Suppositories can be administered to patients who are unconscious or experiencing nausea and vomiting, making them a practical alternative to oral medications.
4) Local treatment:
Suppositories can deliver drugs directly to the site of action for local treatment, such as treating haemorrhoids or vaginal infections.
Disadvantages of suppositories:
1) Patient acceptability:
Some patients may be reluctant to use suppositories due to the invasive nature of the administration route or cultural factors.
2) Limited drug absorption:
The absorption of certain drugs may be limited or erratic in the rectal or vaginal mucosa, which can affect their efficacy.
3) Melting and leakage:
Suppositories can melt or leak at body temperature, causing discomfort and messiness.
4) Incompatibility with certain drugs:
Some drugs may be incompatible with suppository bases or may have poor stability at the melting point of the base.
