Quality Assurance of Pharmaceuticals - A Compendium of Guidelines and Related Materials - Volume 1
(1997; 248 pages) [French] View the PDF document
Table of Contents
Open this folder and view contentsIntroduction
Open this folder and view contents1. National drug regulation
Open this folder and view contents2. Product assessment and registration
Open this folder and view contents3. Distribution
Close this folder4. The international pharmacopoeia and related activities
View the documentGuidance for those preparing or commenting on monographs for preparations to be included in The international pharmacopoeia1
View the documentValidation of analytical procedures used in the examination of pharmaceutical materials1
Close this folderGeneral guidelines for the establishment, maintenance, and distribution of chemical reference substances1
View the document1. Criteria for determining the need for the establishment of chemical reference substances
View the document2. Evaluation of reference substances
Close this folder3. Chemical and physical methods used in evaluating reference substances
View the document3.1 Methods useful for verifying the identity of reference substances
View the document3.2 Purity requirements for reference substances
View the document3.3 Methods used in determining the purity of reference substances
Open this folder and view contents4. Handling and distribution of reference substances
View the document5. Reference materials calibrated against International Chemical Reference Substances
View the document6. Means of promoting effective exchange of information and ensuring cooperation between organizations establishing reference substances
View the documentGeneral recommendations for the preparation and use of infrared spectra in pharmaceutical analysis1
View the documentList of available International Chemical Reference Substances1
View the documentList of available International Infrared Reference Spectra1
Open this folder and view contents5. Basic tests
Open this folder and view contents6. Laboratory services
Open this folder and view contents7. International trade in pharmaceuticals
Open this folder and view contents8. Counterfeit products
Open this folder and view contents9. Training
View the documentSelected WHO publications of related interest
View the documentBack cover
3.1 Methods useful for verifying the identity of reference substances

The identity of a material that is intended to replace an established reference substance of the same molecular constitution may be verified by means of tests that are capable of demonstrating that the characteristic properties of the two specimens are identical. For this purpose, a comparison of their infrared absorption spectra often suffices. Similarly, where a newly proposed reference substance consists of a compound whose structure has been satisfactorily elucidated, its identity may be confirmed by matching the infrared spectra of the material and of an authentic compound. Other highly specific techniques, such as nuclear magnetic resonance spectroscopy, mass spectrometry, or X-ray diffraction crystallography, may also be used for such comparisons.

However, where no authentic specimen of the proposed reference substance is available for comparison and definitive data about its properties are lacking, it may be necessary to verify the identity of the material by applying several analytical techniques currently used to characterize new compounds. Such analytical methods may include elemental analyses, crystallographic studies, mass spectrometry, nuclear magnetic resonance spectroscopy, functional group analyses, infrared spectrophotometry, and ultraviolet spectrophotometry, as well as such other supplementary tests as are necessary and sufficient to establish that the proposed reference material is the required substance.

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