Reducing electrostatic charge on spacer devices and bronchodilator response

Aims Plastic spacers are widely used with pressurized metered dose inhalers (pMDI). Reducing electrostatic charge by washing spacers with detergent ha s been shown to greatly improve in vitro and in vivo drug delivery. We asse ssed whether this finding is associated with an improved bronchodilator res ponse in adult asthmatics. Methods Twenty subjects (age 18-65 years) with a known bronchodilator respo nse inhaled in random order salbutamol from a pMDI (Ventolin(R)) through an untreated new spacer (Volumatic(R)) and through a detergent washed spacer. Patients received the following doses of salbutamol via pMDI at 20 min int ervals: 100 mu g, 100 mu g, 200 mu g, 400 mu g, 800 mu g. Spirometry, heart rate and blood pressure were checked prior to each dose and 20 min after t he last dose. Results There were no differences between baseline forced expiratory volume in 1 s (FEV1) using either spacer (2.61 +/- 0.56 and 2.52 +/- 0.45 l, untr eated and treated with detergent, respectively; mean +/- s.d.). The provoca tion dose required to cause a clinically significant improvement of 10% in FEV1 (PD10) was significantly lower when the detergent treated spacer was u sed (1505 +/- 1335 and 430 +/- 732 mu g, untreated and treated, respectivel y, P < 0.002). Conclusions We have demonstrated an improvement in bronchodilator response, in adult asthmatics, after reducing the electrostatic charge in a spacer d evice by washing it with ordinary household detergent. This finding stresse s the importance of an optimal choice of delivery device for asthma medicat ion.