The invention discloses a preparation method of
piperacillin sodium and
tazobactam sodium for injection. The preparation method comprises the following steps: adding water into a blending tank, cooling to 5-10 DEG C, adding
citric acid, then slowly adding
sodium bicarbonate, and after reacting, reading the pH value and adjusting the pH value to be 6.3-6.6; adding
piperacillin acid into the blending tank, and then dropwise adding the
sodium bicarbonate solution, wherein the pH value in the dropwise adding process is controlled to be less than or equal to 7.0; after dropwise adding, adding
tazobactam acid, and then dropwise adding the
sodium bicarbonate solution, wherein the pH value in the dropwise adding process is controlled to be less than or equal to 7.0; after dropwise adding, carrying out vacuum removal on
carbon dioxide gas by suction, and after the feed liquid in the blending tank is stabilized, reading the pH value and adjusting the pH value to be 6.0-6.5; and carrying out aseptic
filtration and freeze-
drying to obtain raw
powder of
piperacillin sodium and
tazobactam sodium for injection. According to the preparation method, by adding salified
citric acid, the acidity stability of the product is increased, the
decomposition of
piperacillin sodium and
tazobactam sodium is inhibited, and the storage stability of the product is increased.