Drug company Powderject has dropped out of the bidding for rival firm Cantab Pharmaceuticals.

The Oxford company had been regarded as favourite to buy Cantab, based in Cambridge, which is up for sale following the failure of one of its vaccines in October. Powderject, based at Oxford Science Park, is developing a painless injection device and last year bought the UK's largest vaccine maker, Evans Vaccines, which has a factory at Speke, Liverpool.

There are believed to be another 20 companies still in the running to buy Cantab, for sale after its genital warts vaccine failed clinical trials.