Excipient

An excipient is any constituent of a medicinal product other than the active substance and the packaging material. Its definition appears in Directive 2001/83/EC, as amended by Directive 2011/62/EU. Whether diluents, binders, preservatives, colourings, solvents or coating agents, excipients give the medicinal product its form, stability and taste and affect its bioavailability. They are deemed to have no therapeutic action of their own, without being legally neutral for all that.

The regulatory regime for excipients

The qualitative and quantitative composition in excipients appears in the authorisation dossier, and the summary of product characteristics lists them. Certain excipients, known as excipients with known effect, may cause reactions in sensitive patients and must be mentioned in the labelling and package leaflet with the corresponding warnings, in accordance with guidelines adopted at Union level. Excipients are subject to quality requirements, and the marketing authorisation holder must ensure, through a formalised risk assessment, that the appropriate good manufacturing practice is applied to those it uses.

Excipients in the generics regime

The definition of a generic medicinal product requires the same qualitative and quantitative composition in active substances as the reference medicinal product, not the same composition in excipients. A generic may therefore use different excipients, provided it demonstrates that this choice affects neither bioequivalence nor safety. Where the difference concerns an excipient with known effect, patient information must take it into account, and the generics register lists those excipients to inform pharmacist substitution.

Excipients, formulation patents and litigation

Excipients lie at the heart of formulation patents, which protect a specific combination of the active substance with a carrier, a sustained-release agent or a stabiliser. These patents often expire after the basic patent and shape generics litigation, as the competitor seeks a formulation that falls outside the scope of the claims. The debate then turns on claim interpretation and on infringement by equivalence. For the supplementary protection certificate, an excipient is not an active ingredient, and adding one does not make it possible to obtain a new certificate for a product that is already protected.

Key points

An excipient is any component of the medicinal product other than the active substance and the packaging. It has no therapeutic effect of its own but determines the quality, tolerability and bioavailability of the product. A generic may change excipients, provided it demonstrates their safety and proves bioequivalence. In litigation, the competitor’s formulation, as it appears from its authorisation dossier, should be compared precisely with the claims of the formulation patents still in force.

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This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats acts in pharmaceutical patent disputes and on the medicines regulatory questions that accompany them, from the marketing authorisation to the supplementary protection certificate.

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