The couple, who gave their life savings of around pounds 100,000 to found Powderject, put an undisclosed proportion of the funds into a charitable trust and gave pounds 1.2m to the John Radcliffe hospital in Oxford. Dr Drayson said they had made the donation after his wife gave birth in the hospital on Saturday.
The placing, at 800p, of over 9 million shares belonging to founder shareholders followed the expiry of a lock-up period initiated upon the company's flotation two years ago.
The Draysons' options were exercised at just 10p per share. The couple have entered a new agreement which forbids them from selling their remaining 12 per cent Powderject holding until the company is profitable. The rest of the management have signed a new lock-up lasting one year.
Meanwhile, Powderject said Glaxo Wellcome had paid $3.4m (pounds 2.2m) for two further licences to use its patented powderject system, an alternative to needle-based drug delivery methods, in vaccines. The shares closed up 15p at 845p.