The boss of phamaceutical company Powderject hit back at critics telling shareholders he was personally commited to putting his painless injection device on the market, writes Maggie Hartford.

The company, which employs 225 people at Oxford Science Park, has seen its shares plummet from a high of 10.20 to 4.40 over the last year.

Announcing an 18.4m loss for the year, chairman and chief executive Dr Paul Drayson said: "I would like to reassure shareholders that Powderject is in an excellent position to build a sustainable long-term business based on a significant market opportunity, to confirm that there continues to be no compeitition offering the same unique benefits as our powder injection technology and to state that I am confident of leading this company to bring the revolutionary Powderject technology to market."

The Powderject device uses a tiny canister of helium gas to shoot powdered drugs through the skin at supersonic speeds.

Dr Drayson hit back at commentators who questioned whether the long time taken to reformulate medicines into powders was worth it, given that the competing liquid jet technology can use standard medicines.

He added: "While the development of some of our products has taken longer than expected, we have now overcome many of the chllenges cusing these delays."

The company had to postpone a flu vaccine trial, but volunteers are set to be recruited to try its anaesthetic injection, Lidocaine, next year.

Drug company Serono paid 1m to Powderject for developing a fertility drug and Glaxo Wellcome has bought the rights to a DNA vaccine. A glucose test for diabetics is also being developed successfully.

The growth in Powderject's workforce, which increased by half last year, is likely to slow this year, he said.