1. Field of the Invention
The invention relates to a manually actuable dispenser for dispensing dosed amounts of liquid drugs in atomized form.
2. Discussion of the Related Art
It is known that many drugs, for instance calcitonin, are nasally administered: since these drugs are extremely expensive and sometimes they can cause undesired side effects if they are sprayed into nose in exceeding doses, some devices are used for their application by which an exactly predetermined liquid amount, in a totally atomized form, can be dispensed, leaving the lowest residual possible of said liquid unused in said devices.
Indeed, it often happens that the known devices are not suitable for dispensing practically all the liquid substance therein retained, or that the dispensing occurs also at a relatively low pressure, with consequent dropping (and therefore loss) of said liquid outside of the dispensing nozzle of the nasal distributor, or further that the devices have a very complicated structure and therefore extremely expensive, to such an extent to suggest sometimes, at least in part, their re-use.
Devices of such a type are, for instance, described in the patents EP-B-0218840 corresponding to the U.S. Pat. No. 4,921,142 patent, and in the improvement of said last patent, depicted in the EP-A-0388651 and in the pCT/WO/91/13689 (PCT/EP91/00457 application) patents, besides that in the EP-A-0452728 patent.
All the above mentioned patents describe nasal dispensers having a rather complicated structure and therefore expensive, some of which, at the end of their use, keeping in their inside a remarkable amount of the liquid, others not assuring a sufficient seal and insulation of said liquid in the inside of the device during the storage, further, others allowing the liquid dispensing even at excessively low dispensing pressures, with consequent liquid dropping.
To simplify the structure and to therefore control the expenditures of such devices, the French patent FR-B-2625981 proposed a nasal dispensing device comprising a seat in which a piston, which is part of the device itself, extends, in said seat a cylindrical ampoule being insertable which holds the desired amount of the liquid: when said ampoule is inserted in the mentioned seat, the piston, which is part of the device, penetrates in the inside of the ampoule itself, thus allowing the expulsion of the liquid in atomized form when said ampoule is pushed inside its own seat.