THE INTERNAL RESISTANCE OF AN INHALER PLAYS
A CRUCIAL ROLE IN DOSE DELIVERY
WATCH EASYHALER IN ACTION
In addition to medication and dosage, the technical characteristics of a dry powder inhaler (DPI) are of importance when choosing the most suitable treatment for a patient.1,2 Importantly, the internal resistance of an inhaler plays a crucial role in dose delivery.
Figure 1. High-resistance DPI in action. High internal resistance and the generation of turbulent air flow inside a high-resistance dry powder inhaler (Easyhaler). *Easyhaler monotherapy is a high-resistance inhaler3 and Easyhaler combination therapy is a medium-to-high resistance inhaler4.
HIGH INTERNAL RESISTANCE SUPPORTS GREATER LUNG DEPOSITION THAN LOW INTERNAL RESISTANCE1
DPIs with high internal resistance generally provide greater formulation de-agglomeration and lung deposition than devices with low internal resistance.1 Inhalation against high resistance further opens the upper airways, which assists the delivery of medication into the lungs.6 Furthermore, highly turbulent air flow is associated with more efficient de-agglomeration of the drug formulation and the likelihood of greater lung deposition vs devices with low turbulent air flow.2 Patients with COPD, and asthmatic children with exacerbations, were able to use high resistance DPIs effectively.6 Among COPD patients, the vast majority (98%) were able to achieve a sufficient inhalation flow through the high resistance DPI (Easyhaler®) for optimal drug delivery.3 High internal resistance is therefore an important technical feature of a DPI.7
Figure 3. Adapted from Levy ML, Carroll W, Izquierdo Alonzo JL, Keller C, Lavorini F, Lehtimäki L. Understanding dry powder inhalers: key technical and patient preference attributes. Adv Ther 019;36(10):2547–57.
DPI = Dry Powder Inhaler, pMDI = Pressurised Metered dose Inhaler
**This article refers to UK brand names. Within the clinical papers, the brand names reflect the location of where the studies took place
March 2021 / RESP-746(1)
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- Chrystyn H, Haahtela T. Real-life inhalation therapy – inhaler performance and patient education matter. Eur Respir Dis 2012;8(1):11-18.
- Malmberg L, Rytilä P, Happonen P, Haahtela T. Inspiratory flows through dry powder inhaler in chronic obstructive pulmonary disease: age and gender rather than severity matters. Int J of Chron Obstruct Pulmon Dis 2010;5:257–62.
- Kirjavainen M, Mattila L, Vahteristo M, Korhonen J, Lähelmä S. Pharmacokinetics of Salmeterol and Fluticasone Propionate Delivered in Combination via Easyhaler and Diskus Dry Powder Inhalers in Healthy Subjects. J Aerosol Med Pulm Drug Deliv 2018;31(0):1-8.
- Malmberg LP, Evarard M,Haikarainen J, Lahelma S. Evaluation of in vitro and in vivo flow rate dependency of budesonide/formoterol Easyhaler. J Aerosol Med Pulm Drug Deliv 2014;27(5)329–40.
- Demoly P, Hagedoorn P, de Boer A, Frijlink H. The clinical relevance of dry powder inhaler performance for drug delivery. Respiratory Medicine 2014;108(8):1195–1203.
- Chrystyn H. Closer to an ‘ideal inhaler’ with the Easyhaler. Clin Drug Invest 2006;26(4):175–83.
- Levy ML, Carroll W, Izquierdo Alonzo JL, Keller C, Lavorini F, Lehtimäki L. Understanding dry powder inhalers: key technical and patient preference attributes. Adv Ther 2019;36(10):2547–57.
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