Next week Accolate, the oral treatment for asthma, goes on sale in the crucial US market. It is the first time an oral treatment has been available outside Japan.
The company has had to employ an extra 100 salesmen to cope with the anticipated demand for a product which is more convenient than traditional inhalers.
Some analysts forecast that sales from the drug, which is already on sale in Finland and Ireland, could reach $500m.
It is the first drug which has been developed purely in the US.
Accolate may not secure blockbuster status, however, Amistar, Zeneca's revolutionary new fungicide, is set to achieve the accolade when it comes officially to market in the next few weeks.
The agrochemical division has developed Amistar using new chemistry which restricts its side effects on the vegetation it is treating.
It will be launched into a market worth around $5bn a year. Analysts forecast it could snatch more than 10 per cent of the market, making it a blockbuster in agrochemical terms.
Amistar can be used to treat anything from golf courses to bananas. A new plant to manufacture the product will be officially opened in Scotland next month. Trial production batches have already gone on sale.
Zeneca is also hoping that its agrochemicals division will receive a further boost next week when it hopes to secure Chinese approval for the development of a new paraquat production plant which is planned for Nantong, which is 200 miles north of Shanghai.
The green-field $80m investment is awaiting clearance of minor points and may be approved during a state visit from senior Chinese politicians next week.