[Time course of drug concentrations in nebulizers and nebulized solutions]

The drug concentrations in nebulizers and nebulized solutions generated by the ultrasonic nebulizer OMRON NE-U10B and the jet nebulizer INSPIRON NEBULIZER 002305 were examined. With the ultrasonic nebulizer, increases in the concentrations of saline, DSCG and isoproterenol in the nebulizer were observed; the concentrations of those in the nebulized solutions also increased. The increase was most dramatic just before the solution was emptied. No degradations of DSCG or isoproterenol were detected in the nebulized solutions, indicating that these drugs are stable against ultrasonic nebulization. An increase in the drug concentrations in the jet nebulizer was also observed. The concentrations of the nebulized solutions also increased, but the concentrations in the nebulized solution were lower than those in the nebulizer at any time. On inhalation therapy, it is important to give consideration to these concentration changes. The nebulizer should not, for example, be refilled with a new drug solution.