Effect of different accessory devices on the dose delivered from pressurised metred-dose inhalers

Improved aerosol delivery of bronchodilators to chronic obstructive pulmonary disease (COPD) subjects is a cornerstone in the treatment approach. Drug delivery and response are improved with the use of accessory devices [spacers and valved holding chambers (VHCs)] with metred-dose inhalers (pMDIs). However, different accessory devices are available in the market with different properties that could affect aerosol delivery. Thus, this study aimed to assess the relative lung deposition and systemic bioavailability and compare bronchodilator response of salbutamol delivered using different accessory devices attached to pMDIs.

Twelve healthy subjects and twelve COPD subjects inhaled 300 μg salbutamol (3 pMDI puffs) using five different accessory devices with either masks or mouthpieces (Able, Aerochamber plus flow Vu, Dolphin chamber, Tipshaler spacer, and modified Drink bottle spacer). Urine samples were collected thirty minutes post-dosing and cumulatively for the next twenty-four hours, to determine and compare the relative lung deposition [0-0.5 hour excretion of urinary salbutamol (USAL0.5)] and systemic bioavailability [0.5-24 hours excretion of urinary salbutamol (USAL24)] of salbutamol from the selected accessory devices. Also, the difference between pre and post-inhalation forced expiratory volume in one second (ΔFEV₁ %) of predicted was determined for each accessory device.

Urinary excretion of salbutamol (both USAL0.5 and USAL24 samples) in COPD subjects was significantly (P < .05) lower than in healthy subjects for all accessory devices. USAL0.5 and USAL24 in non-antistatic spacers (modified Drink bottle spacer and Dolphin chamber spacers) were significantly lower (P < .05) than that for antistatic spacers (Aerochamber plus flow Vu, Able and Tips-haler). No significant difference in USAL0.5 and USAL24 was observed between facemasks and mouthpieces. There was a significant difference (P < .05) in ΔFEV₁ % of predicted values between COPD subjects and healthy subjects. However, within the COPD group and the healthy group there was no significant difference in ΔFEV₁ % of predicted values between all accessory devices or between with mouthpiece or with a mask.

COPD subjects had lower aerosol delivered compared with healthy subjects. Anti-static accessory devices delivered a higher amount of aerosol compared with non-antistatic accessory devices. Even though the presence of a significant difference in aerosol delivery between non-antistatic and antistatic accessory devices no significant difference was found in the ΔFEV₁ % between all accessory devices.