The invention relates to the technical field of medicines, and provides a
nalmefene hydrochloride injection and a preparation method thereof, every 1000 injections comprise the following components in parts by weight: 2.0 g of
nalmefene hydrochloride based on
nalmefene, 18g of
osmotic pressure regulator, 0.05-0.1 g of
meglumine, and the balance of water for injection to 2000mL. The preparation method comprises the following steps: S1, adding the
osmotic pressure regulator and the
meglumine in a prescription dosage into the water for injection which accounts for 90% of the total amount of the prescription dosage, stirring until the
osmotic pressure regulator and the
meglumine are dissolved, and regulating the pH value to 3.5-4.0 through a
hydrochloric acid solution; s2, adding a prescription amount of
nalmefene hydrochloride into the solution in the step S1, stirring until the
nalmefene hydrochloride is dissolved, and adjusting the pH value to 3.5-3.8; and S3, adding water for injection to the total amount, uniformly stirring, filtering, canning into an
ampoule bottle, sterilizing, carrying out lamp detection for leakage detection, and packaging. By adding a small amount of meglumine, the amount of the dinalmefene
impurity generated by long-term placement and oxidation of the
nalmefene hydrochloride injection can be reduced, adverse reactions possibly caused by a large amount of meglumine are reduced, the content of the dinalmefene
impurity is maintained at a low level, and the use safety of the injection is improved.