| 摘要 |
Powder delivery system comprises an elongate housing (40) forming an air flow path between its ends. A mouthpiece is formed at the proximal end for drawing the air through the housing. A desiccant (56) is provided in the flow path. A measured amt. of particles of the powder (58) are introduced into the flow path, the powder being in communication with the desiccant. Suction at the mouthpiece causes air to flow along the flow path where it entrains the particles of dry powder for discharge through the mouthpiece. Pref., at the distal end of the device is a porous element (56) contg. a desiccant, e.g. anhydrous CaSo4 particles. The porous element is pref. porous polyethylene with a multitude of irregular passageways extending from one end to the other. The desiccant being impregnated in the polymer matrix and the air flowing through the passageways. A matrix (58) is mounted downstream and contains a measured amount of dry powder therapeutic cpd. Pref., the matrix consists of a filter rod of polymer fibres, esp. polyethylene, with the dry powder dispersed through it. Alternatively, the powder and desiccant can both be impregnated in the matrix eliminating the need for the porous element. The mouthpiece is a tubular housing formed of a length of flexible polymer, esp. polyethylene or polypropylene. |
