The invention discloses a purification method of
semaglutide. The method comprises the following steps: (1) dissolving a crude
semaglutide product in dilute
ammonia water, carrying out water bath andfiltering successively, and collecting a filtrate; (2) performing
gradient elution by taking a reverse-phase
silica gel filler as a
stationary phase, a
salt solution with a pH value regulated to 7-9 by
ammonia water as a mobile phase A and
acetonitrile as a mobile phase B, collecting fractions, and performing rotary
evaporation to remove a part of the
solvent to obtain a primarily-purified solution; (3) carrying out
gradient elution by taking the reversed-phase
silica gel filler as the
stationary phase, a
saline solution with a pH value adjusted to 2-3 by
phosphoric acid as the mobile phase Aand a
mixed solution of
acetonitrile and isopropanol as the mobile phase B, collecting fractions, and carrying out rotary
evaporation to remove a part of the solvents so as to obtain a secondarily-purified solution; and (4) carrying out
gradient elution by taking the reverse-phase
silica gel filler as the
stationary phase, an
aqueous solution of
ammonium bicarbonate as the mobile phase A and
acetonitrile as the mobile phase B, collecting fractions, carrying out rotary
evaporation, and carrying out freeze-
drying so as to obtain saltless refined
peptide of
semaglutide, wherein the saltless refined
peptide has purity of greater than 99.5% and an individual
impurity content of less than 0.1%. The method is simple and convenient to operate and facilitates large-scale preparation of semaglutide.