Application of solid state nuclear magnetic resonance and chemometric tools to the characterization of polimorphism in drugs

Abstract

Polymorphism is the capacity of a molecule to crystallize in several forms and it is a serious problem for the pharmaceutical companies. Depending on the form which the drug crystallizes, its physical and chemical properties are completely affected. Then, the therapeutic efficiency of the pharmaceutical solids can be totally suppressed, and also lead to some undesirable effects to the organism. The formation of several polymorphs in drugs depending on synthetic process and/or the conditions of storage. To control the problem is necessary to know all the polymorphs possibly formed in each of these two stages and the actions of each one. The characterization is necessary, but it is still complicated because in almost of the cases is required the use of several techniques. In this way, it does not exist, in Brazil, any specific law to insurance the control of this problem. Among several techniques used in the characterization of polymorphism, solid state NMR have been gained a good position, since its application has been shown many advantages, by comparing it to other techniques. In this way, this project intends to develop an analytical methodology, in solid state NMR, which could be useful in order to contribute to the establishment, in Brazil, of a specific legislation to control the problems related to the polymorphism. The molecules which will be studied in this work are mebendazole and diethylcarbamazine, both used to treat very common diseases in Brazil. We intend to use solid state NMR, manly observing carbon-13 nucleus, and allied to the data processing, we also intend to use methods of chemometric analysis, to maximize the number of information that could be extracted from these results. (AU)