Impurezas elementales en las sustancias activas: una perspectiva general.

Elemental impurities in Active Substances: a general perspective The elemental impurities must meet high quality requirements, in order to achieve this goal several analytical parameters such as a low impurity content is the capital importance. In this situation, several types of impurities can be mentioned for example: organic and inorganic impurities, mutagenic compounds, residual solvents, and elemental impurities. The relevance of the impurities is high because these compounds are toxic for the patient and can cause adverse effects in patients therefore they should be limited. Specifically the elemental impurities are residues of metal elements that come from the unit operations used in the manufacturing process of an active substance. These contaminant are classified in the ICHQ3D guide in four groups according to their toxicity and their presence in an active substance is explained by the synthesis process (raw materials, solvents, water) or by the wear of the productive equipment (reactors, centrifuges, dryers, mills). In order to determine the quantities of these compounds analytical methods are a fundamental part, since they must be sufficiently sensitive and specific. The evaluation through a risk analysis provides the theoretical information of the potential metallic impurities present in an active substance; a case study exemplifies this section. Another important aspect to take in account is the control of the presence of metal impurities in synthetic processes, so having an overview of the control methods is a paramount importance in order to establish the appropriate control strategy. In this section, a reported case is described. Finally, general trends in purification of an active substance provide an insight into developments in this area. This paper includes a brief review of the previously mentioned topics. [ABSTRACT FROM AUTHOR]