Como ser um caçador de impurezas em substâncias ativas: uma metodologia e estudos de caso

Introduction. The content of impurities in active substances and pharmaceutical forms is a very im-portant topic since a high content of byproducts could put the population at risk. Depending on the knowledge of the structure, there are different limits. Therefore, it is mandatory to know the origin and chemical structures of the impurities in order to limit them. When it comes to manufacturing processes, there is always a small possibility that a process may have an excursion in some variable either due to human error or equipment failure. Intention. Therefore, it is necessary to know how to manage this type of problem and, most importantly, avoid recurrence. To achieve this objective, it is necessary to develop a methodology that provides a guideline to follow. Knowledge of the structure, as well as scientific research, will help propose appropriate operational corrective measures to avoid recurrence and be able to continue manufacturing a product that complies with current regulations and specifications. The implementation of actions that lead to the rapid control of problems is of capital importance for the pharmaceutical industry with the objective of having alternative control measures and continuing to manufacture since patients expect these medicines. Results. In this review, a methodology is presented to elucidate organic impurities either in active substances or in pharmaceutical forms. Ten theoretical cases will be presented and exemplified with similar cases described in the literature. The main tools used to carry out research will also be discussed. Likewise, a perspective of the analytical advances used to elucidate impurities will be provided. Finally, some control proposals will be commented.