Suppositories aren’t sexy – let’s just acknowledge that point right upfront. Science can be sexy, in a “wow, it’s amazing what science can do!” sort of way.
But as far as patients are concerned, suppositories don’t qualify.
Drug developers, however, think otherwise – and for a wide range of reasons. Once relegated to the treatment of anal and vaginal conditions, suppositories have become the darling of drug delivery scientists due to their ability to increase absorption and circumvent the liver while having fewer side effects.
The thought of using a suppository for a headache may sound strange, but drug companies – mindful of the benefits – hope the general aversion to this form shifts. It already has in some European countries, but there remains work to be done in the rest of the world.
What’s a Suppository?
Despite their lack of popularity, suppositories are one of the oldest forms of medicine. Modern suppository use began in the late 1800s and evolved into its current form throughout the 20th century. Suppositories can be defined as a solid dosage form administered through insertion in the rectum, vagina, or in rare cases, the urethra.
The first rectal suppositories were a combination of medicinal substances and materials such as baked honey, soap, tallow, or horn.
Today there are two types of suppositories:
- Lipophilic fat-based suppositories which melt at body temperature, releasing the drug into the body.
- Hydrophilic water-based suppositories requiring water in order to release the drug.
Suppositories can act as a topical dosage form to address localized pain, and they can also serve as a drug delivery system to target systemic pain. In a suppository, the drug is diffused like all topical forms—in a passive fashion. Rectal suppositories are the most common form, treating a range of illnesses. Vaginal and urethral suppositories are more targeted.
The primary use for rectal suppositories includes:
- Allergies
- Anxiety
- Constipation
- Fever
- Hemorrhoids
- Motion sickness
- Nausea
- Pain and itching
- Seizures
- Mental health conditions, such as schizophrenia or bipolar disorder
Vaginal suppositories treat localized conditions:
- Bacterial or fungal infections
- Vaginal dryness
In rare cases, men may use a urethral suppository for erectile problems.
These lists of approved uses continue to grow as drug companies increasingly focus on this dosage form. Companies are exploring suppositories that can administer HIV anti-viral drugs, prevent pregnancy, and protect against sexually transmitted diseases.
Suppositories benefit the patient
Even though patients are hesitant to accept suppositories, there are many benefits to the dosage form. Notably, these benefits address challenges facing certain patient groups:
- Elderly or infant patients who cannot swallow.
- Epileptic patients unable to take oral medicine.
- Patients with a blockage preventing oral medicine from moving through the digestive tract.
- Individuals who are vomiting and can’t keep anything down.
- Patients that aren’t adhering to foul-tasting medicine.
Suppository dosage form: pharmacokinetics
With increased bioavailability to absorbable tissue, suppositories possess pharmacokinetic advantages.
Since suppositories bypass first-pass metabolism, they are a great alternative to medicine that is ruined in the gastrointestinal tract, breaks down too quickly, or irritates the gastric mucosa. Suppositories have the unique ability to quickly deliver high doses without the aid of special equipment or storage conditions.
With the rising geriatric population, suppository-based drug delivery is a simple solution for these patients. The market has taken note of the growing interest. The global pharmaceutical suppositories market was valued at $1,410.93 million in 2020 and is projected to reach $2,402.46 million by 2030, registering a CAGR of 5.7% from 2021 to 2030.
Challenges: lack of research and practical concerns with suppositories
While there are clear advantages to suppositories, there are indeed challenges. The most glaring challenge is the lack of research around suppositories. In their article for Therapeutic Delivery, Anthony S. Ham and Robert W. Buckheit Jr. explain that this form is “remarkably unspecific,” lacking systematic and rationally designed formulations.
Other challenges include storage and packaging issues. Certain oil-based suppositories must be refrigerated in warm climates to avoid crystallization or melting. Hydrogel-based suppositories must have specific packaging to keep them from absorbing moisture and melting.
There are also practical concerns from patients, including:
- Irritation around the area of insertion.
- Leakage, which not only is messy but also raises concerns about receiving proper dosage.
- The lack of general acceptance of suppository use.
For scientists, there are challenges during the formulation of suppositories. For example, it can be difficult to determine which excipients will keep the dose high and still maintain shape, solubility, and stability. Furthermore, the availability and cost of the materials used in manufacturing suppositories can be a concern, especially in certain countries.
A Growing Niche
Suppository manufacturing is a very niche field, and drug formulation and dosage form factor design can be challenging. [That’s why it’s so important to find a manufacturer with experience with this dosage form. LGM Pharma is a leader in suppositories manufacturing, producing 35 million doses annually. We have the skill, expertise, and the state of art equipment for suppository manufacturing.]
Despite the stigma of suppositories, they are a versatile dosage form with the ability to address issues that other dosage forms cannot. And beyond the practical benefits, there are opportunities to solve unmet medical needs with suppositories.