Suppository formulation and manufacturing

The modern pharmaceutical industry offers a wide range of routes of administration and pharmaceutical forms for delivering active ingredients to the site of action. Among these routes, the oral route is the most widely used, with tablets and capsules in particular. Alongside these are the topical, parenteral and rectal routes. The latter is one of the oldest routes of administration, with enemas and suppositories as the main pharmaceutical forms.

The European Pharmacopoeia (EP) defines a suppository as a solid unit preparation whose shape, volume and consistency are suitable for rectal administration.

Suppositories may contain one or more active substances dispersed or dissolved in the suppository mass. These masses are either hydrophilic, dissolving or dispersing on contact with the water in the rectal ampoule, or lipophilic, melting at rectal temperature. The suppository masses referenced in the EP are macrogols and gelatinous mixtures, for hydrophilic masses, and hemisynthetic glycerides and cocoa butter, for lipophilic masses. The US Pharmacopoeia (USP) and the Japanese Pharmacopoeia (JP) also define a suppository as a pharmaceutical form suitable for administration in the rectum or vaginal cavity. Suppository masses are identical to those described in the EP, with the addition of hydrogenated vegetable oils, fatty acid esters and polyethylene glycols (PEGs).

Suppositories are typically produced by molding, either in metal molds on a laboratory scale, or directly in plastic or aluminum blisters on an industrial scale. The EP also describes numerous pharmacotechnical tests to verify the quality and functionality of these formulations.

Although suppositories are not the preferred dosage form for patients, they are nonetheless essential when the patient is unable to swallow a tablet (infants, elderly people with swallowing problems, adults with vomiting problems, etc.). The pediatric and geriatric populations are particularly targeted by this dosage form.

The main active ingredients sold in suppository form for a local effect are glycerine or bisacodyl for constipation, or mesalazine for irritable bowel syndrome. For a systemic effect, the main ingredients are paracetamol, ibuprofen, diclofenac and oxycodone for pain and fever .

However, the suppository market remains a niche market with low growth rates. The annual growth rate for suppository bases is estimated at 2.7% worldwide and 3.2% in Europe (source: