 For almost 25 years, he was responsible for chemical manufacturing and international production at Janssen Pharmaceutica, and together with Chinese partners, he established Xian Janssen Pharmaceutical.After the opening of China in 1978, their first factory was set up by Joos Horsten in Hanzhong, after which a second and larger factory followed in Xi'an.From 1992 to 1997, he continued his career at Solvay Pharmaceuticals, a Belgian chemical and pharmaceutical multinational, as Vice-President Technical Affairs, and in 1997 established his own company, as a consultant to Chinese pharmaceutical companies.