[Spacer, Aerosol Therapy through Space and Time]

Area of Science:

• Pharmaceutical technology
• Respiratory medicine
• Drug delivery systems

Background:

• Pressurized metered dose inhalers (pMDIs) are widely used for respiratory conditions.
• The use of spacers with pMDIs is common practice to improve drug delivery.
• Coordination issues and oropharyngeal deposition are key challenges in pMDI therapy.

Purpose of the Study:

• To review and evaluate the application of spacers with pMDIs.
• To analyze the impact of guidelines and product authorizations on spacer use.
• To assess the interplay between pMDI characteristics and spacer performance.

Main Methods:

• Literature analysis of studies on pMDI spacers.
• Revision of effects of spacers on aerosol deposition and delivery.
• Evaluation of current guidelines and regulatory conditions for pMDI spacer use.

Main Results:

• Spacers generally mitigate coordination problems and reduce mouth-throat deposition for pMDIs.
• Some newer pMDIs may not require spacers as their aerosol quality is already optimized.
• Significant variations in delivered dose and aerosol quality occur with different spacers, potentially altering efficacy by up to 100%.

Conclusions:

• For pMDIs approved post-2009, the Summary of Product Characteristics (SmPC) should recommend specific spacers based on in vitro/in vivo data.
• Using a non-recommended spacer can lead to unpredictable changes in the delivered dose.
• Careful consideration of spacer selection is crucial for consistent and effective pMDI therapy.