For the last decade, YONSUNG R&D center has intensively focused on the process development of prostaglandins, which eventually made YONSUNG a prominent commercial supplier of prostaglandin APIs in the world. In the course of their process development we have accumulated sophisticated knowledge and experience in organic synthesis as well as intelligent command of chemical engineering. Besides prostaglandins, we plan to expand our interest to HPAPIs (highly potent active pharmaceutical ingredients) having challenging structures such as opioid APIs, calcitriol analogs and further to oncological APIs. YONSUNG R&D center has state of art facility in analytical research which include 300 MHz NMR, HPLC, GC, UV, IR. We routinely perform analytical method development and validation which are indispensable in DMF (Drug Master File) registration as well as in evaluation of the quality of an API. YONSUNG R&D has expertise in filing DMF in foreign countries: We have registered 11 DMFs in Japan; 4 DMFs in EU; 2 DMFs in China; 1 DMF in USA. In addition, 12 DMFs are in the registration process in various foreign countries. Our mission is to become the best process R&D in Korea and eventually in the world, particularly in the domain of HPAPIs sector.