Efeito da granulometria e taxa de aquecimento na transição de fase do cloridrato monoidratado de lamivudina

• Autor(a) principal: Pereira, Marcus Vinícius
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9341
• topic: Transição de fase; Polimorfo; Lamivudina; Phase transition; Polymorph; Lamivudine; CIENCIAS EXATAS E DA TERRA::QUIMICA

The main objectives of the pharmaceutical industry are focused on the synthesis and characterization of chemical compounds that possess biological activity and that are useful in the treatment of diseases and symptoms that affect the populations. Some drugs may, in the solid state, present different arrangements of their molecules within a crystal, a phenomenon known as polymorphism. Active Pharmaceutical Ingredient (APIs) are mostly produced and marketed in the form of solid formulations. The therapeutic efficacy of each API, however, is directly related to its characteristics in the solid state. Thus, the control and understanding of its solid-state physico-chemical peculiarities, such as formulated products or pure substances, is an important part of the development process of new drugs. Thus, the aim of this work is to verify how granulometry and heating rate can influence the phase transition of lamivudine monohydrate hydrochloride to corresponding anhydrous polymorphs. The characterization of the polymorphic forms occurred through thermal analysis and powder X-ray diffractometry where it was possible to identify the solid phases by means of the superposition of experimental and simulated diffractograms. In predominantly normal conditions of granulometry and heating rate, it was evidenced that the lamivudine hydrochloride monohydrate undergoes transition to the more abundant anhydrous lamivudine hydrochloride (polymorph I). However, some samples under very specific particle size conditions of the order of 203.0 Å and controlled heating, with initial temperature of 25ºC and final temperature of 90ºC (at rates of 5ºC min-1 or 10º C.min-1) also showed lamivudine anhydrous hydrochloride II polymorph. Therefore, this study reinforces the need for systematic investigation of the impact of physical-chemical parameters on the polymorphic composition of active pharmaceutical ingredients, and consequently on their therapeutic performances.