Evaluation of Preliminary Bronchodilation Effect on Aerosol Delivery from a Dry Powder Inhaler for Patients with Chronic Obstructive Pulmonary Disease with Suboptimal Peak Inspiratory Flow Rate.

Background: Suboptimal peak inspiratory flow rates (PIFR) are common in patients with chronic obstructive pulmonary disease (COPD), hindering effective medication dispersion and aerosol delivery. This study aimed to assess whether administering a preliminary bronchodilator dose via a pressurized metered-dose inhaler (pMDI) improves aerosol drug delivery via dry powder inhaler (DPI) in patients with COPD with suboptimal PIFR (< 60 L/min), compared with those with optimal PIFR (≥ 60 L/min).

Methods: Overall, 24 patients with COPD were evaluated. PIFR was measured using the In-Check Dial^© G16, dividing patients into optimal and suboptimal groups. All patients received a 200 µg dose of salbutamol via Diskus^® DPI. Patients with COPD with suboptimal PIFR received two puffs (100 µg each) preceded by a preliminary salbutamol dose administered via pMDI^®. Urine salbutamol levels (USAL30) and salbutamol that was eluted from filters (SALF) were measured after 30 min to assess lung deposition through high-performance liquid chromatography (HPLC).

Results: Patients with COPD with suboptimal PIFR without a preliminary dose had significantly lower USAL30 than the optimal group (4.99% versus 6.18%, p = 0.013). A preliminary dose improved USAL30 in the suboptimal group but did not reach statistical significance (5.45% versus 4.99%, p = 0.071).

Conclusions: A significant difference in aerosol drug delivery was observed between optimal and suboptimal groups without a preliminary dose, suggesting that inhaler selection in patients with COPD may need to be individualized on the basis of inspiratory flow capability. Administering a preliminary dose of pMDI^® before using a DPI minimally affects the suboptimal inhalation through DPI.