Suppositories are pharmaceutical dosage forms designed for insertion into the rectum, vagina, or urethra to deliver the active pharmaceutical ingredients (APIs) directly into the surrounding tissues or body circulation. They are solid or semi-solid formulations that melt or dissolve at body temperature, allowing the drug to be absorbed. The most common shape of suppositories is the "bullet" or "torpedo" shape. However, other common suppository shapes include round and elongated ovals, tampons, and "teardrops" or "cones".

Fig. 1 Illustration of suppository delivery. (Ham AS, et al. 2017)

The ideal suppository matrix should be non-toxic, non-irritating, inert, and compatible with the drug. It should also dissolve or disintegrate in the presence of mucus secretions or melt at body temperature to allow drug release. Protheragen-ING offers a one-stop shop for suppository development, designing suppository formulations based on the characteristics of the API and the client's development goals. We strictly adhere to suppository manufacturing guidelines and regulations such as ISO 9001 and ISO 13485 to ensure the quality, safety, and efficacy of suppositories.

Types of Suppositories

Through a combination of excipient matrices, Protheragen-ING can develop the following two types of suppositories:

• Lipophilic fat suppositories - easily dissolve typically insoluble small molecule drugs

Oleaginous bases include theobroma oil and synthetic triglyceride mixtures.

Oleaginous bases melt at body temperature for easy insertion and drug release. These suppositories are ideal for rectal use.

• Hydrophilic Water-Based Suppositories - easier to support drug delivery of soluble drug compounds

The water-soluble matrix contains either glycerin gelatin or polyethylene glycol (PEG) polymers. It is not affected by body temperature and requires water to dissolve the suppository and release the drug. These suppositories are suitable for vaginal use where there is a lot of localized fluid.

Advantages of Suppositories

• Local administration - Suppositories can bypass the digestive system and deliver the drug directly to the site of action, avoiding the first-pass metabolism that occurs with oral drugs.
• Rapid absorption - Rectal and vaginal mucosa have a rich blood supply, which allows the drug in the suppository to be rapidly absorbed into the body's circulation.
• Avoidance of gastrointestinal problems - Some drugs may cause gastrointestinal irritation or malabsorption in the stomach or intestines. Suppositories provide an alternative route of administration for such medications.
• Suppositories are particularly useful for patients who have difficulty swallowing.

Preparation Process of Suppositories

Protheragen-ING prepares all types of suppositories by a fusion method.

1. Selection of the substrate

A suitable substrate is selected based on the nature of the drug, the desired release characteristics, and the route of administration.

2. Weighing and melting

The substrate is weighed and melted using a suitable method (e.g. water bath or microwave oven). Ensure that the temperature does not exceed the melting point of the substrate.

3. Adding API

Mix the API into the melted substrate. This can be done either by dissolving the drug in a suitable solvent and adding it to the melted matrix or by dispersing the powdered drug into the melted matrix and mixing it thoroughly.

4. Pouring into mold

The mixture is poured into a pre-sterilized suppository mold. The mold can be made of plastic, metal, or silicone and should be of a size suitable for the intended route of administration.

5. Cool and solidify

Allow the suppositories to cool and solidify at room temperature or under refrigeration. Once solidified, remove them from the mold and store them in an appropriate container.

Applications for Suppositories

Protheragen-ING can assist in the development of a wide range of suppository drug delivery systems, including but not limited to the following.

• Analgesics: Some painkillers, such as acetaminophen or ibuprofen, can be formulated as suppositories for localized or generalized pain relief.
• Antiemetics: Medications used for the relief of nausea and vomiting, such as ipecac or ondansetron, may be administered as suppositories when oral administration is not feasible.
• Antipyretics: Suppositories containing antipyretics such as acetaminophen can be used to reduce fever, especially in children.
• Anti-inflammatory medications: Suppositories can deliver anti-inflammatory medications (such as indomethacin or diclofenac) directly to the affected area to treat conditions such as hemorrhoids or proctitis.
• Hormones: Some hormone medications, including progesterone or estrogen, can be formulated as vaginal suppositories for hormone replacement therapy or birth control.
• Anti-constipation agents: Suppositories containing laxatives (e.g., bisacodyl or glycerin) may relieve constipation by stimulating bowel movements.
• Antifungals: Vaginal suppositories may provide antifungal drugs such as clotrimazole or miconazole for the treatment of vaginal yeast infections.

If you are interested in our suppository formulation development services, please contact us for detailed information and services.