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
Open this folder and view contents2. Elements in the INN system
Close this folder3. Principles for selection of INNs
View the document3.1 General rules
View the document3.2 Use of stems
View the document3.3 Stereoisomers
View the document3.4 Radioactive compounds
View the document3.5 Specific groups of biological compounds
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
 

3.3 Stereoisomers

An INN for a new chemical entity does not routinely specify the stereoisomeric state of the molecule in the nonproprietary name. If the stereochemistry has been determined, then this information is presented in the chemical name(s) to identify the substance. An INN can, therefore, identify the racemic mixture (e.g. ibuprofen, tetramisole), the levo- isomer (e.g. amifostine, lofentanil, prenalterol, remoxipride, quadazocine), or the dextro form (e.g. butopamine). Subsequently if an INN is needed for a different enantiomer or for the racemic form, the following prefixes should be added to the existing INN:

(a) For the levo form, the lev-/levo- prefix is used, e.g. levocarnitine, levamisole.
(b) For the dextro form, the dex- prefix is used, e.g. dexamisole, dexibuprofen.
(c) For the racemic form, the rac-/race- prefix is used, e.g. racepinefrine.

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