Hand-held dispenser

A hand-held dispenser for dispensing a pharmaceutical product is disclosed. The dispenser has a housing 1 providing a duct 12. A frangible membrane 44 is provided in the duct 12. A probe 3 with a piercing tip 35 is mounted in the duct 12 and arranged such that, in use the piercing tip 35 pierces the frangible membrane 44. An air compression device 2 is provided to compress air for expelling a pharmaceutical product through the probe 3 and a channel 46 is provided to substantially equalise the pressure in the air compression device 2 and the pressure above the frangible membrane 44. The ability to substantially equalise the pressure in the bellows 2 and the pressure above the frangible membrane 44 on the sheath provides for a more consistent release of pharmaceutical product when the frangible membrane is pierced. This is because the compressed air from the bellows 2 which expels the pharmaceutical product through the probe 3 does not encounter a sudden change in pressure as it passes the pierced frangible membrane 44 with the entrained pharmaceutical product. In use, when compressed air is used to expel a pharmaceutical product through the probe 3, the air path through the probe 3 has a lower resistance than the channel 46 to substantially equalise the pressure in the air compression device and the pressure above the frangible membrane 44. This ensures that the majority of the compressed air is used to expel the pharmaceutical product. The piercing tip 35 preferably comprises a generally annular cutting edge 36 on an end portion of the probe with an interruption 37 in the generally annular cutting edge 36.