Dry powder inhalers (DPIs) have become an integral part of treatment protocols for patients suffering from chronic respiratory conditions like Chronic Obstructive Pulmonary Disease (COPD) and asthma. The effectiveness of these devices, however, can vary significantly due to a multitude of factors, with device resistance being one of the most critical. A comprehensive study conducted by Kruger et al. in 2014 delves deep into this particular aspect, shedding light on how it influences the performance of DPIs1.
Device resistance in DPIs plays a pivotal role in attaining optimal flow rates, thereby ensuring the efficient utilization of inspiratory airflow for powder dispersion and deagglomeration. These processes are paramount for the therapeutic effect of the medication. The study offers an assessment of the device resistance and its variability among currently marketed DPIs used for treating COPD or asthma1.
Kruger and his team measured the pressure drop and corresponding flow rate at a defined pressure point or a constant flow rate (0–100 L/min). They employed a test system equipped with a mass flow meter and a differential pressure sensor, ensuring an accurate and consistent methodology1.
Certain studies found out that Breezhaler® device demonstrated highest inspiratory flow rate versus other dry powder inhaler devices.1,2,3 This attribute makes it an effective choice for delivering medication to the lungs1. Understanding the device resistance when choosing a DPI for patient use is crucial as variations could potentially impact the effective delivery of medication.
Table 11
Inspiratory flow rates through marketed inhalers (3 batches/product, 3 inhalers/batch = 9 inhalers/product)
|
Inhaler |
Inspiratory flow rate at 4.0 kPa pressure drop (L/min) |
RSD of flow rate (%) |
Inspiratory device resistance (√kPa.min/L) |
|
Breezhaler® |
111 |
4.0 |
0.017 |
|
Aerolizer™ |
102 |
2.8 |
0.019 |
|
ELLIPTA™¹ |
74 |
1.5 |
0.027 |
|
Novolizer® |
72 |
0.9 |
0.027 |
|
Accuhaler™ |
72 |
9.1 |
0.027 |
|
Genuair® |
64 |
0.8 |
0.031 |
|
Turbohaler® Symbicort® |
58 |
1.0 |
0.035 |
|
NEXThaler® |
54 |
0.9 |
0.036 |
|
Turbohaler® Pulmicort®² |
54 |
1.9 |
0.039 |
|
Twisthaler® |
47 |
1.3 |
0.044 |
|
Easyhaler® |
41 |
3.7 |
0.050 |
|
HandiHaler® |
37 |
1.4 |
0.058 |
¹ n=5 inhalers, 1 batch; ² n=6 inhalers, 1 batch
In conclusion, the study by Kruger et al. provides a valuable contribution to our understanding of DPIs, with particular emphasis on the role of device resistance. As we continue to strive for improved treatment outcomes for patients with COPD and asthma, such research will undoubtedly play a pivotal role. The Breezhaler®, with its optimal inspiratory flow resistance, emerges as an effective DPI choice, underscoring the importance of considering device resistance in DPI selection and design.
References
- Kruger, Et. Al. Inspiratory flow resistance of marketed dry powder inhalers (DPI). European Respiratory Journal 2014 44: 4635.
- Dederich, Et. Al. Inspiratory Flow Profiles Generated By Patients With COPD Through The Breezhaler® Inhaler And OtherMarketed Dry Powder Inhalers. Am J Respir Crit Care Med 191;2015:A5793.
- Altman, Et. Al. Comparison of peak inspiratory flow rate via the Breezhaler®, Ellipta® and HandiHaler® dry powder inhalers in patients with moderate to very severe COPD: a randomized cross-over trial. BMC Pulm Med. 2018 Jun 14;18(1):100.