Patent ID: 8766002

Claim:
A method of preparation of iodixanol, characterized by comprising the following steps: a) dimerization of 5-acetamido-N,N′-bis (2,3-dihydroxypropyl)-2,4,6-triiodo-isophthalamide (compound A) to prepare iodixanol, obtaining a solution of dimerization; wherein said dimerization step comprises dissolving Compound A in an excessive amount of alkali, neutralizing the excess alkali by a boron-containing acidic substance of salts thereof, and adjusting the pH to 10-13; b) purification of the solution of dimerization by a macroporous adsorption resin chromatographic column, obtaining iodixanol crude product with a purity more than 97%; or desalination of the solution of dimerization by anionic and cationic ion exchange resins or macroporous adsorption resin chromatographic column, obtaining desalted iodixanol crude product; c) recrystallization of the iodixanol crude product with mixed solvents containing 2-methoxyethanol, obtaining iodixanol with a purity more than 99%.