The United States Pharmacopoeia (USP) has enrolled Hanmi Pharmaceutical’s reflux esophagitis drug, Esomezol, making Hanmi the first Korean pharmaceutical company to gain international accreditation through USP, the company said Wednesday.

Esomezol (compound: esomeprazole strontium) was the first incrementally improved drug for gastroesophageal reflux disease in the country to receive the U.S. FDA’s marketing approval in August 2013.

“The recent USP enrollment will strengthen sales and marketing in the U.S. for Esomezol, which was approved by the FDA as the first domestically modified drug,” said Woo Jong-soo_우종수, CEO of Hanmi Pharmaceuticals_한미약품.

Hanmi is currently selling Esomezol in 14 U.S. states through R2 Pharma (CEO: Robbie H. Cline), a drug import and sales company. Hanmi plans to expand its sales from the southern region of the U.S. to the eastern and western coasts, it said.

The company had previous run-ins with AstraZeneca on the patent front over Esomezol, which is an incrementally modified drug of AstraZeneca’s Nexium. Nexium is a blockbuster product that recorded more than 2 trillion won ($1.78 billion) in sales in the U.S. alone.

The USP is a scientific nonprofit organization that sets global standards for medicines, food ingredients and dietary supplements around the world. The U.S. Food and Drug Administration enforces these standards, which are also used by more than 140 countries.