Technology for preparing high-purity tacrolimus

The present invention provides a high-purity preparation of tacrolimus process, comprising the steps of (1) of dried crude tacrolimus 1-2 parts by volume of 7-9 parts by weight of tetrahydrofuran were added, dissolved by heating, add water, filtration; (2) purification: C18 reverse phase column, the column height 15 ~ 40cm, diameter 15 ~ 50cm; diameter higher than 1: 0.8 to 1: 4; mobile phase volume ratio of tetrahydrofuran: acetonitrile: water: acetic acid = 3 to 5: 0.5 to 1.5: 6 to 8: 0.01 to 0.05; temperature 20 ~ 50 ℃; flow rate of 1-5L / min; detection wavelength 220nm; (3) the eluate were combined, concentrated by evaporation, crystallization and drying. By the process of the present invention, tacrolimus significantly improved purity and yield, purity 99.5%, the single impurities not more than 0.3%, the total impurity content of not greater than 0.5%, yield of 50-80%.