DU polymorphisme de la khelline

Abstract We have obtained several polymorphs of khellin by recrystallization in some organic solvents under different temperature and pressure conditions: form I ( T f 153.0 °C), form III ( T f 149.0 °C), form IV ( T f 145.0 °C). We have also isolated and identified using thermoanalytical methods and X-ray diffraction four polymorphs which translate during heating into form I , and three which translate into form III . Form II ( T f 150.00 °C) has been identified with other polymorphs; this form has been isolated previously during heating and cooling cycles. Some samples were constituted by several polymorphs. Khellin is a good example of a drug showing many possibilities of hydrogen bonds between molecules.