The invention relates to polymorphic substances of
obeticholic acid and a preparation method thereof. According to the invention, a novel
crystallization method is adopted to prepare
obeticholic acid polymorphic substances. The preparation method for a
crystal form I comprises the following steps: dissolving
obeticholic acid in a good
solvent, adding a certain proportion of a poor
solvent when complete dissolving is just realized under the condition of refluxing, decreasing a temperature, carrying out cooling so as to allow a
crystal to be precipitated, and carrying out filtering and
drying. The preparation method for a
crystal form II comprises the following steps: dissolving obeticholic acid in an
organic solvent, carrying out refluxing, decreasing a temperature, carrying out cooling so as to allow a crystal to be precipitated, and carrying out filtering and
drying. The method provided by the invention has the following advantages: the crystallized obeticholic acid polymorphic substances are stable; meanwhile, operation is simple and practicable, and a conventional
solvent can be used; the disadvantages of complex steps, difficult
crystallization, poor
repeatability and
instability of a disclosed preparation method are overcome; and the method is suitable for industrial production.