Zeneca (officially Zeneca Group PLC) was a British multinational pharmaceutical company headquartered in London, United Kingdom. It was formed in June 1993 by the demerger of the pharmaceuticals and agrochemicals businesses of Imperial Chemical Industries into a separate company listed on the London Stock Exchange.[1]

In 1999, Zeneca and the Sweden-based pharmaceutical company Astra AB merged to form AstraZeneca plc.[2][3]

Zeneca's largest therapeutic area was oncology, in which its key products included Casodex, Nolvadex and Zoladex.[4] Other key products included heart drug Tenormin.[5]

"Zeneca" was an invented name created by the branding consultancy Interbrand.[6] Interbrand had been instructed to find a name which began with a letter from either the top or bottom of the alphabet and was phonetically memorable, of no more than three syllables and did not have an offensive meaning in any language.[6]

In December 1994, Zeneca agreed the acquisition of 50% of Salick Health Care, an operator of cancer care centres in the United States, in a transaction which valued Salick at US$440 million.[7] Zeneca announced the sale of its textile colours business to the German group BASF in May 1996.[8] Zeneca announced it would purchase the remaining 50% of Salick Health Care that it did not already own on 28 March 28 1997.[9] In December 1997, Zeneca acquired the US fungicide operations of Ishihara Sangyo Kaisha, along with the international distribution rights to four recently developed fungicides, herbicides and pest control products, for US$500 million.[10][11]

In May 1998, Zeneca announced that Tom McKillop, then the head of its drugs division, would succeed Sir David Barnes as chief executive, with Barnes becoming non-executive chairman of the company.[12] In November 1998, Zeneca announced that it would sell its Zeneca Specialties division, including its biocides, industrial colours, life science molecules, performance and intermediate chemicals and resins activities.[13] On 11 December 1998, Zeneca and Astra AB announced a £48 billion merger.[14] In February 1999, it was reported that Zeneca would sue the US Food and Drug Administration over its decision to allow Gensia Sicor to produce a generic version of its anaesthetic Diprivan.[15] The merger between Zeneca and Astra AB was completed in April 1999, forming AstraZeneca plc.[16]