Suppositories

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.