Improved Process for the Preparation of Naloxegol Oxalate, an Opiod Receptor Antagonist.

The present article discloses an improved and robust commercial process of the modern medicine naloxegol oxalate, which is used to treat opioid-induced constipation. The synthesis originates from the easily available key starting material, viz., naloxone, and ends with the oxalate salt of naloxegol (a pharmaceutically acceptable salt). This novel route has a very high yield and purity greater than 99.5%, substantially free from impurities (less than 1%).