Electro-hydrodynamic atomization of drug solutions for inhalation purposes

Monodisperse aerosols show therapeutic advantages, but they are difficult t o generate. A new method (electrohydrodynamic atomization) is described. A high voltage is applied to a nozzle through which a solution, containing di ssolved drug, is pumped. At the nozzle tip, a liquid cone is formed and a s tream of monodisperse droplets is released. The droplet diameter is governe d by the density, conductivity, and the flow rate of the fluid. The droplet s are charged and need to be neutralized. Therefore, a corona discharge sys tem is used. Methylparahydroxybenzoate was used as a model drug, and additi onal data were generated by using beclomethasone dipropionate (BDP). At a f low rate of 1 ml/h and 0.5% methylparahydroxybenzoate, 1.58-mum particles w ere produced with a geometric SD of 1. 18. Increasing the flow rate to 3 ml /h and the concentration to 3% resulted in 4.55-mum particles with a geomet ric SD of 1.29. The experiments with BDP resulted in similar particle sizes . The mass of BDP was found to range between 1.42 and 6 mug/l air. Aqueous solutions cannot be sprayed by using this setup. This method can be used to deliver antiasthma drugs to patients.