The properties of pentamidine isethionate aerosols produced by an ultr
asonic nebuliser frequently used in clinical practice have been invest
igated. The mass median diameter of the aerosols was initially 5.1-5.6
mum, depending on the volume of solution atomized and the output sett
ing of the nebuliser. The aerosol size tended to decrease, and the sol
ution temperature increase with time. Between 57 and 74% of drug place
d in the nebuliser was delivered during use, the remainder being assoc
iated with the device.