Emprego da RMN no estado sólido em estudos de complexos supramoleculares de fármacos
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Data
2016-03-15Autor
Xavier, Tatielih Pardim de Oliveira
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Many pharmaceutical solids are able to adopt more than one crystalline form, and this property is called polymorphism. Currently 80-90% of the drugs are marketed as in solid forms and a very common problem is the low solubility of these drugs, particularly in aqueous media. Depending on how a drug crystallizes, its physical and chemical properties can be changed, which may also result in changes in its solubility. Before this problem the crystals engineering appears as a strategy to improve the properties of the solid state related to the efficacy of the drugs through the development of new crystalline forms. Multicomponent molecular crystals can be prepared from supramolecular synthons forming approach by crystallization methods involving the optimization of conditions for the formation of these novel crystalline forms. In this context, this study aimed to use the solid state NMR for study of supramolecular chemistry the three antiparasitic drugs (secnidazole, albendazole and mebendazole) and one antiretroviral (tenofovir disoproxil fumarate) using a set of one-dimensional techniques (CP-TOSS, CP-NQS and CP-PI) for the carbon-13 and nitrogen-15 nucleus as well as two-dimensional (1Hx13C FSLG HETCOR). Solid state NMR was used as the primary analytical tool for characterizing the crystalline forms obtained in this study, as in the prior characterization of Active Pharmaceutical Ingredient (APIs) used as raw material, being demonstrated the applicability of this technique in the analysis of new
formulations. The data obtained were of great importance in the study of these solid
dosage forms which can contribute to the structural study of dosage forms, identify
polymorphic forms of drugs, detect phase transitions in both API as in commercial
samples and check for interactions molecular (intramolecular and intermolecular) by
means of two-dimensional NMR. In this work it was shown that this technique is
configured as an important tool for the characterization of new polymorphs but they
certainly should be applied in conjunction with other techniques in order to take
advantage of the complementarity provided when different techniques are used in
combination. This work intends to consolidate the use of NMR in the solid state in
Brazil as a tool for the characterization of the crystalline forms of drugs and also for
the analysis of drugs, which has been few explored so far.