CrystEngComm, 2014, 16,8555-8562
DOI: 10.1039/C4CE01157K, Paper
Amanda Laura Ibiapino, Rafael Cardoso Seiceira, Altivo Pitaluga, Antonio Carlos Trindade, Fabio Furlan Ferreira
aCenter of Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Av. dos Estados, 5001, Santo André, Brazil
bLaboratory of Solid State Studies (LEES), Farmanguinhos, FIOCRUZ, Av. Comandante Guaranys, 447, Rio de Janeiro, Brazil
cReal Time Process and Chemical Analysis Development Center (NQTR), Chemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rua Hélio de Almeida, 40, Rio de Janeiro, Brazil
dFederal Institute of São Paulo (IFSP), Av. Mogi das Cruzes, 1501, Suzano, Brazil
Crystal structure determination of form I of anhydrous rifampicin by X-ray powder diffraction data. Crystal morphology prediction revealed a good agreement with the images of the crystals.
Rifampicin is a first-line drug widely used in the treatment of tuberculosis both in the intensive and in the treatment phase. In this work we characterized the crystal structure of form I of anhydrous rifampicin mainly by using X-ray powder diffraction data combined with the Rietveld method. Other complementary techniques such as Fourier transform infrared spectroscopy and thermal analysis were also employed. It crystallized in a monoclinic crystal system with space group C2 and the following unit cell parameters: a = 25.8846(2) Å, b = 14.2965(2) Å, c = 14.2796(2) Å, β = 122.98(1)°, V = 4432.81(7) Å3, Z = 4, Z′ = 1 and ρcalc = 1.23310(2) g cm−3. A BFDH model was used to inspect the crystal morphology prediction, and great similarity with crystals observed on an optical microscope was found. The FTIR spectrum confirmed the results obtained by X-ray powder diffraction, which indicates that all the functional groups involved in H bonding are intramolecularly connected. This polymorphic form presented a thermal stability up to approximately 230 °C.