Plastic bottles as spacers for a pressurized metered-dose inhaler: In vitro characteristics

Homemade spacer devices are commonly used by children with asthma to improv e aerosol deposition from pressurized metered dose inhalers (pMDI); however , the efficacy and efficiency of these devices are not fully characterized We determined the quality of fine particle fraction (< 4.7 mum) and ultrafi ne particle fraction (< 3.3 mum) of three bottles (from 280 ml to 500 ml) c ommonly used as spacers in Trinidad and Tobago and compared their performan ce to the commercial available valved holding chamber (OpT) and pMDI These data were obtained in vitro using a cascade impactor. All 3 bottles and the OpT were similar (p > 0.05) in reducing the amount of albuterol emitted as large particles (> 4.7 mum) to less than 10 mug. The different sized bottl es (from 280 ml to 500 ml) produced identical quantities of albuterol in th e fine particle and ultrafine particle ranges (p > 0.05). All of the sample bottle spacers emitted a higher amount (p < 0.002) of fine and ultrafine p articles than the OpT and pMDI alone. The OpT resulted in a significantly h igher fraction of fine particles (p < 0.05) and a greater quantity of drug (p < 0.05) in the ultrafine range as compared to the MDI only. The sizes of particles obtained from the bottle spacers are those that have a high prob ability of reaching the lower airway; however, the clinical relevance of th ese findings remains to be determined.