A comparison of lung deposition patterns between different asthma inhalers

Area of Science:

• Pulmonary drug delivery
• Respiratory medicine
• Pharmaceutical technology

Background:

• Inhaled therapies are crucial for asthma treatment and prophylaxis.
• Pressurized metered dose inhalers (pMDIs), pMDIs with spacers, and dry powder inhalers (DPIs) are common delivery devices.
• Drug deposition in the lungs is influenced by device type, formulation, and patient technique.

Purpose of the Study:

• To compare lung deposition efficiency and oropharyngeal deposition across different inhaled asthma medication delivery devices.
• To evaluate the impact of device design and patient factors on drug delivery to the lungs.

Main Methods:

• Comparative analysis of lung deposition from pMDIs, pMDIs with spacers, and DPIs.
• Assessment of factors influencing drug deposition, including aerosol formulation, patient inhalation technique, and device design.
• Evaluation of oropharyngeal deposition as a key outcome measure.

Main Results:

• The majority of drug dose from pMDIs is deposited in the oropharynx.
• Spacer devices can reduce oropharyngeal deposition, but their effect on lung deposition is variable.
• One specific DPI (Turbuhaler) demonstrated twice the lung deposition of a pMDI, with lower intersubject variability and reduced oropharyngeal deposition.

Conclusions:

• Device design significantly impacts inhaled drug deposition in the lungs and oropharynx.
• DPIs, particularly devices like Turbuhaler, may offer advantages in terms of lung delivery efficiency and reduced upper airway deposition compared to pMDIs.
• Optimizing inhaler selection and technique is essential for effective asthma management through inhaled therapies.