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Study of polymorphic forms of raw materials of ritonavir and lopinavir with the use of powder x-ray diffraction and the Rietveld method

Grant number: 17/16499-5
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): November 01, 2017
Effective date (End): October 31, 2018
Field of knowledge:Physical Sciences and Mathematics - Physics - Condensed Matter Physics
Principal Investigator:Fabio Furlan Ferreira
Grantee:Lucas Barboza Moreira Pinheiro
Home Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil

Abstract

The correct identification and quantification of polymorphs (polymorphism is the property of a substance to crystallize in more than one crystal structure) in both raw materials and finished substances is of great interest to researchers involved in processes for the development of new crystalline forms or in processes of quality control. One of the best-known examples in the scientific literature was related to ritonavir, which underwent structural transformation over time. One of the most used techniques in the structural characterization of pharmaceutical ingredients is the powder X-ray diffraction. When used in conjunction with the Rietveld method of refinement of crystal structures, it is possible to perform the identification and quantification of phases reliably. Even if one does not have information about the crystal structure of a given material or even if the information is known partially (unit cell parameters and spatial group, for example), the method can be used with the implementation of the methodology known as PONKCS - Partial Or No Known Crystal Structure - in the Topas-Academic program.In this work the student will study basic concepts about polymorphism, crystallography and powder X-ray diffraction in order to identify and quantify polymorphs of crystalline forms of raw materials of ritonavir and lopinavir. (AU)