Spacers and Valved Holding Chambers

Area of Science:

• Respiratory medicine
• Pharmaceutical technology

Background:

• Pressurized metered-dose inhalers (pMDIs) present challenges in coordinating actuation with inhalation.
• High drug deposition in the oropharynx can lead to local and systemic side effects.
• Inconsistent pMDI output in clinical practice necessitates devices to improve drug delivery.

Purpose of the Study:

• To review the role of spacers, particularly valved holding chambers (VHCs), in optimizing pMDI use.
• To identify factors influencing drug delivery efficiency from VHCs.
• To outline recommendations for optimal VHC usage and patient technique.

Main Methods:

• Review of existing studies on VHC design and function.
• Analysis of factors affecting drug delivery variability.
• Synthesis of recommendations for clinical practice.

Main Results:

• VHCs help overcome coordination issues and reduce oropharyngeal deposition.
• Spacer design factors (volume, shape, material) significantly impact delivered dose.
• Low or anti-static materials are available to minimize electrostatic charge issues.
• Optimal use varies by patient age and coordination ability.

Conclusions:

• VHCs are crucial for improving pMDI efficacy and safety.
• Careful consideration of VHC design and patient technique is essential for maximizing lung deposition.
• Further optimization of VHCs and usage guidelines can enhance therapeutic outcomes.