Dr. Jan Constant Janssen (Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

, Vlimmeren, 18 September 1895-Antwerp, 15 April 1970), was a Belgian

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 physician and businessman. He was the third child (out of four) of Adriaan Victor Janssen (1854-1942) and Anna Catharina Eelen (1855-1929). He went to highschool in Hoogstraten

Hoogstraten

Hoogstraten is a municipality located in the Belgian province of Antwerp. The municipality comprises the city of Hoogstraten proper and the towns of Meer, Meerle, Meersel-Dreef, Minderhout and Wortel,...

 and studied medicine at the Catholic University of Leuven

Catholic University of Leuven

The Catholic University of Leuven, or of Louvain, was the largest, oldest and most prominent university in Belgium. The university was founded in 1425 as the University of Leuven by John IV, Duke of Brabant and approved by a Papal bull by Pope Martin V.During France's occupation of Belgium in the...

 and the University of Ghent. On 16 April 1925, he married Margriet Fleerackers (Turnhout, 5 January 1897-Vosselaar

Vosselaar

Vosselaar is a municipality located in the Belgian province of Antwerp. The municipality only comprises the town of Vosselaar proper. On January 1, 2006 Vosselaar had a total population of 10,142. The total area is 11.85 km² which gives a population density of 856 inhabitants per km².There are 3...

, 23 September 1973), together they had four children. Their oldest son, Paul Janssen

Paul Janssen

Paul Adriaan Jan, Baron Janssen was the founder of Janssen Pharmaceutica, a pharmaceutical company with over 20,000 employees. In 2005 he finished as runner up, after Father Damien, in the poll for The Greatest Belgian organized by the regional Flemish television...

, would become one of the most successful scientists in pharmaceutics.

Career

He started his career as a family physician in Turnhout, but in addition he was interested in business too. In 1921, he met Ladislas Richter in Vienna

Vienna

Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

, who was the son of Gedeon Richter, who owned a pharmaceutical factory in Budapest

Budapest

Budapest is the capital of Hungary. As the largest city of Hungary, it is the country's principal political, cultural, commercial, industrial, and transportation centre. In 2011, Budapest had 1,733,685 inhabitants, down from its 1989 peak of 2,113,645 due to suburbanization. The Budapest Commuter...

, Hungary

Hungary

Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

. In 1933, he acquired the right to distribute the pharmaceutical products of Richter

Gedeon Richter Ltd.

Gedeon Richter Plc. , the largest pharmaceutical factory in Hungary, was established by Mr. Gedeon Richter, a pharmacist in 1901. Mr. Richter is not only the founder of the company, but the establishment of his firm also marked the beginning of the development of the Hungarian pharmaceutical industry...

, the Hungarian

Hungary

Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

 pharmaceutical company, for Belgium, the Netherlands and Belgian Congo

Belgian Congo

The Belgian Congo was the formal title of present-day Democratic Republic of the Congo between King Leopold II's formal relinquishment of his personal control over the state to Belgium on 15 November 1908, and Congolese independence on 30 June 1960.-Congo Free State, 1884–1908:Until the latter...

. On 23 October 1934, he founded the N.V. Produkten Richter in Turnhout. In 1937 Constant Janssen acquired an old factory building in the Statiestraat 78 in Turnhout for his growing company, which he epxanded during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 into a four-storey building. In 1938 he closed his practice as a family physician and concentrated his effort of the expansion of his pharmaceutical business. His wife managed the production, quality control, and the administration of the company.

Still a medical student, his son Paul Janssen helped with the development of Perdolan. After World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the brandname of the products was changed into Eupharma, and later the company would evolve into Janssen Pharmaceutica

Janssen Pharmaceutica

Janssen Pharmaceutica is pharmaceutical company, established in Belgium in 1953 by Paul Janssen. Its headquarters are located in Beerse, in the Campine region of the province of Antwerp, Belgium. It was created not as a subsidiary of a chemical factory but solely with the aim of conducting...

.

Source

• Dirk Collier (Ed.), Dr. Constant Janssen, Janssen Pharmaceutica, 1996