Guidelines on the Use of International Nonproprietary Names (INNs) for Pharmaceutical Substances
(1997; 41 pages) View the PDF document
Table of Contents
Open this folder and view contents1. General introduction
Close this folder2. Elements in the INN system
View the document2.1 Proposed INNs
View the document2.2 Recommended INNs
View the document2.3 Names for radicals and groups
View the document2.4 Modified INNs (INNMs)
View the document2.5 Cumulative list of INNs
Open this folder and view contents3. Principles for selection of INNs
View the document4. Protection of INNs
Open this folder and view contents5. How to apply for an INN
View the document6. References for supporting material
View the documentAnnex 1: Background information on the INN programme
View the documentAnnex 2: General principles for guidance in devising international nonproprietary names for pharmaceutical substances
View the documentAnnex 3: List of common stems used in the selection of INNs
View the documentAnnex 4: Specific groups of biological compounds
View the documentAnnex 5: WHA46.19 - Nonproprietary names for pharmaceutical substances
View the documentAnnex 6: Procedure for the selection of international nonproprietary names for pharmaceutical substances
View the documentAnnex 7: Applications for INNs through national authorities (addresses)
View the documentAnnex 8: INN request form
 

2.4 Modified INNs (INNMs)

In principle, INNs are selected only for the active part of the molecule which is usually the base, acid or alcohol. In some cases, however, the active molecules need to be expanded for various reasons, such as formulation purposes, bioavailability or absorption rate. In 1975 the experts designated for the selection of INN decided to adopt a new policy for naming such molecules. In future, names for different salts or esters of the same active substance should differ only with regard to the inactive moiety of the molecule. For example, oxacillin and ibufenac are INNs and their salts are named oxacillin sodium and ibufenac sodium. The latter are called modified INNs (INNMs).

Before the existence of this rule, some INNs were published for salts. In such cases, the term “modified INN” may also be used for a base or acid. For example, levothyroxine sodium was published as an INN and levothyroxine may thus be referred to as an INNM.

Please see also chapter 2.4 for radicals and groups (see also 2.4) which are used in conjunction with INNs and which are also referred to as INNM.

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