Crude medicine for hypoglycemic medicine

The invention relates to a crude medicine for a hypoglycemic medicine, and particularly relates to a medicinal crude medicine. The active component of the crude medicine is a compound in the formula I as shown in the specification, or an acid addition salt thereof, for example, phosphate or solvate thereof, for example, hydrate, optionally comprises an impurity D as the impurity, and preferably comprises an impurity N as the impurity. The content of the impurity D relative to free alkali of the compound in the formula 1 is lower than 0.5%; the content of the impurity N relative to the free alkali of the compound in the formula I is lower than 0.5%. The invention also relates to a pharmaceutical composition prepared from the crude medicine, a preparation method of the crude medicine, and a pharmaceutical purpose of the crude medicine. The crude medicine disclosed by the invention can be applied to prevention and treatment of II-type diabetes mellitus, hyperglycemia, insulin resistance, obesity, hypertension and complications thereof.