The output of budesonide from spacer devices assessed under simulated breathing conditions

Background: Spacer devices are increasingly used to aid inhalational therap y, and many different devices are available. Patient and spacer size and sp acer static charge may affect drug delivery, brit the optimum spacer size a nd method of reducing static charge is not certain Objective: We sought to determine the output of budesonide from 3 different spacer devices when assessed by using simulated breathing at different tid al volumes and to assess the effect of washing and handling the spacer on d rug output, Methods: Three spacer types were assessed: 2 polycarbonate spacers, the Aer ochamber and the Nebuhaler, and the metal Nebuchamber or Non-Electrostatic- Spacer. Breathing was simulated by using a sinus flow pump. Metered-dose in halers of budesonide 200 mu g were actuated into the spacer, which was atta ched to the breathing simulator for 5 simulated breathing cycles. Budesonid e was collected on a filter placed between the spacer and breathing simulat or and was assayed by HPLC, Spacers were assessed after they had been washe d briefly in water, after they had been washed briefly in cetrimide solutio n in an attempt to reduce their static charge, and after they had been hand led to simulate normal use, Zn separate experiments budesonide particle siz e from the spacers was measured by using a multistage liquid impinger, Results: Drug output from the Nebuchamber was greater than that from the ot her 2 spacers, especially at lower tidal volumes, With 150 mt of tidal volu me, the Nebuchamber delivered 36% of the nominal dose to the filter versus 13% from the Nebuhaler and 7% from the Aerochamber. The output from the Aer ochamber and Nebuhaler increased linearly with tidal volume, but this was n ot the case with the Nebuchamber, in which output was constant at tidal vol umes of 150 mt and above. Compared with washing in tap water, neither washi ng the spacers in 0.1% cetrimide solution nor vigorous wiping with a paper towel changed their output. Thirty-eight percent of the drug from the Nebuc hamber was contained in particles smaller than 4.7 mu m in diameter compare d with 47% from the Nebuhaler and 53% from the Aerochamber, Conclusions: The Nebuchamber increases in vitro budesonide delivery compare d with the polycarbonate spacers tested but delivers a greater percentage o f the drug in large particles. No increase in delivery with tidal volume wa s seen with the Nebuchamber, which would deliver a higher dose of drug per kilogram of body weight to smaller patients. Briefly washing the polycarbon ate spacers in water or in a weak detergent solution, simulating household washing, did not make them as effective as the metal spacer, Further resear ch is needed to determine a practical washing and handling method to reduce static charge on polycarbonate spacers.