Potential of a cyclone prototype spacer to improve in vitro dry powder delivery

Copyright The Author(s) 2013. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedPurpose: Low inspiratory force in patients with lung disease is associated with poor deagglomeration and high throat deposition when using dry powder inhalers (DPIs). The potential of two reverse flow cyclone prototypes as spacers for commercial carrierbased DPIs was investigated. Methods: Cyclohaler®, Accuhaler® and Easyhaler® were tested with and without the spacers between 30-60 Lmin-1. Deposition of particles in the next generation impactor and within the devices was determined by high performance liquid chromatography. Results: Reduced induction port deposition of the emitted particles from the cyclones was observed due to the high retention of the drug within the spacers (e.g. salbutamol sulphate (SS): 67.89 ± 6.51 % at 30 Lmin-1 in Cheng 1). Fine particle fractions of aerosol as emitted from the cyclones were substantially higher than the DPIs alone. Moreover, the aerodynamic diameters of particles emitted from the cyclones were halved compared to the DPIs alone (e.g. SS from the Cyclohaler® at 4 kPa: 1.08 ± 0.05 μm vs. 3.00 ± 0.12 μm, with and without Cheng 2, respectively) and unaltered with increased flow rates. Conclusion: This work has shown the potential of employing a cyclone spacer for commercial carrier-based DPIs to improve inhaled drug delivery.Peer reviewe

Clarifying the dilemmas about inhalation techniques for dry powder inhalers: integrating science with clinical practice

This review integrates pharmaceutical science with routine clinical practice to explain why inhalation manoeuvres through a dry powder inhaler (DPI) should start with a gentle exhalation, away from the inhaler. Place the inhaler in the mouth and ensure the lips form a tight seal. This should be followed by an immediate forceful inhalation that is as fast as possible and continued for as long as the patient can comfortably achieve. Although this is universally accepted, there has been a lot of attention on inhalation flow as an indicator of adequate inspiratory effort. This has led to the wrong assumption that inhalation flows through each DPI should be the same, and that low flows through some DPIs suggest that dose delivery is impaired. Most miss the concept that inhalation flow together with the resistance of the DPI combine to create a turbulent energy which de-aggregates the formulation and provides an effective emitted dose. A low flow through a DPI with high resistance generates the same turbulent energy as fast flow with low resistance. Therefore, depending on the device, different inhalation flows are compatible with potentially effective use. Flow measurements should be a guide to train patients to inhale faster. The focus of inhaler technique training should be the use of the above generic inhalation manoeuvre