Its best known products are the valves and plastic gadgets used by asthmatics to inhale Ventolin.
Much of the profits advance is due to the acquisition of Tenax, a moulder of plastic medical, surgical and pharmaceutical devices.
Tenax was Bespak's first big move in North America, and it paid pounds 33m for the company last March. In the half-year Tenax contributed pounds 10.4m to total group sales of pounds 27m but more than half the overall operating profit.
The acquisition was partly paid for by issuing new shares. Earnings per share - a better guide to performance than profits - rose a more modest 19 per cent.
Sales of a device to apply a Merck treatment for eyes were also particularly strong. Bespak lists Boehringer, Glaxo and Rhone-Poulenc Rorer among its other customers.
Bob King, the chairman and chief executive, said the interim performance was 'satisfactory despite the climate of recession and uncertainty'.
He stressed that development of the US operations was the key to the company's future prosects and said Bespak was building its operations there.
The pre-tax figures benefit from pounds 180,000 of interest received compared with a charge of pounds 41,000 last time. The dividend is lifted 14 per cent to 4p.
The shares have enjoyed a strong run since devaluation in September. With a 5p rise to 622p yesterday, they have gained 38 per cent since the early autumn.Reuse content