Artículos de revistas
Thermal studies on polymorphic structures of tibolone
Fecha
2010Registro en:
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, v.102, n.1, p.233-241, 2010
1388-6150
10.1007/s10973-009-0580-8
Autor
ARAUJO, Gabriel Lima Barros de
FARIA, Dalva Lucia Araujo de
ZAIM, Marcio Henrique
CARVALHO, Flavio Machado de Souza
ANDRADE, Fabio Ramos Dias de
MATOS, Jivaldo do Rosario
Institución
Resumen
Tibolone polymorphic forms I (monoclinic) and II (triclinic) have been prepared by recrystallization from acetone and toluene, respectively, and characterized by different techniques sensitive to changes in solid state, such as polarized light microscopy, X-ray powder diffractometry, thermal analysis (TG/DTG/DSC), and vibrational spectroscopy (FTIR and Raman microscopy). The nonisothermal decomposition kinetics of the obtained polymorphs were studied using thermogravimetry. The activation energies were calculated through the Ozawa`s method for the first step of decomposition, the triclinic form showed a lower E (a) (91 kJ mol(-1)) than the monoclinic one (95 kJ mol(-1)). Furthermore, Raman microscopy and DSC at low heating rates were used to identify and follow the thermal decomposition of the triclinic form, showing the existence of three thermal events before the first mass loss.