What are the pharmaceutical excipients

Auxiliary materialsIn addition to the pharmacologically active ingredients, pharmaceuticals also contain numerous auxiliary substances that are important for production, stability, taste, appearance and bioavailability. Excipients have traditionally been viewed as inert. However, they can also be involved in the effects that affect pharmacokinetics and cause undesirable effects.

synonymous: pharmaceutical excipients, excipients, pharmaceutical excipients


On the one hand, drugs contain the active ingredients that mediate the pharmacological effects. On the other hand, they consist of auxiliary materials that are used for the production or to support and regulate the effect of the drug.

An exception are the placebos, which only consist of excipients and do not contain any active ingredients.

Auxiliaries can be of natural, semi-synthetic and synthetic (artificial) origin. They should be non-toxic and microbially harmless. Compatibility with the containers, with the other auxiliary materials and with the active ingredients is also important. Their proportion in terms of number and quantity is usually higher than that of the active ingredients.

Finished medicinal products very rarely contain any excipients - one example is the anesthetic sevoflurane, which consists only of the active ingredient.


Auxiliaries perform a wide range of functions in pharmaceuticals. They are for durability, stability, shape, weight, consistency, taste, appearance, promotion of release, absorption and bioavailability, adjustment of pH and osmolarity, protection and of importance for the manufacturing process.

Excipients were traditionally considered to be pharmacologically inert. However, they are important for both pharmacodynamics and pharmacokinetics and may also be active themselves (e.g. ointment bases, essential oils).

Auxiliary materials can be seen as problem solvers. For example, water is quickly contaminated with microbes. So preservatives are added to the preparation. Or fat-soluble substances dissolve poorly - an emulsifier mediates between the hydro- and lipophilic phase.

Relationship to the food

Most pharmaceutical excipients are also used in the preparation of processed foods - as food additives. You can therefore also be assigned an E number.

Obligation to declare

The so-called full declaration of auxiliary materials has been in force in Switzerland since January 1, 2019. All auxiliary substances contained must be listed in both the specialist information and the patient information (drug approval ordinance, AMZV).


The following list shows a selection of groups of excipients for the manufacture of pharmaceuticals. A detailed list of excipients can be found at the end of this article.

unwanted effects

Some excipients can cause undesirable effects. For example, the parabens, lanolin and peanut oil can cause allergic reactions. Sweeteners and colors have been criticized for various reasons. Aluminum compounds have also been suspected of being harmful to health for a number of years.

Additives such as lactose, mannitol, gluten, sorbitol and fructose can cause gastrointestinal disorders in sensitive people.

Benzalkonium chloride can discolour contact lenses and butylated hydroxyanisole can irritate the skin.

Some excipients are controversial because of their origin, such as gelatine, which is obtained from animals, or petroleum products such as petroleum jelly and paraffins, which are not sustainable. Palm oil is also criticized for ecological reasons.

Sugar can damage teeth and alcohol triggers central nervous disorders.

The antioxidant sodium metabisulfite is found in solutions for injection containing adrenaline for the treatment of severe allergic reactions. But it can also cause allergies itself.

List of excipients in medicinal products (selection) ABCDEFGHIJKLMNOPRSTVWX see also

Active ingredients, dosage forms, additives

  • Pharmaceutical product information (CH)
  • Medicines Approval Ordinance (AMZV)
  • European Medicines Agency (EMA)
  • European Pharmacopoeia PhEur
  • Handbook of Pharmaceutical Excipents, 6th Edition, 2009
  • Pharmaceutical Technology Textbooks
  • Pifferi G., Restani P. The safety of pharmaceutical excipients. Farmaco, 2003, 58 (8), 541-50 Pubmed
  • Pharmacopoea Helvetica
  • Swissmedic

Conflicts of Interest: None / Independent. The author has no relationships with the manufacturers and is not involved in the sale of the products mentioned.

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This article was last changed on April 14, 2021.
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