Title : The impact of inspiratory parameters on the performance of marketed dry powder inhalers using patients’ inhalation profiles
Abstract:
Dry powder inhalers (DPIs) are passive devices used to administer inhaled medication for the management of asthma and chronic obstructive pulmonary disease (COPD). DPIs require patients to generate a sufficient internal turbulent airflow force during each inhalation to deaggregate the powdered drug formulation into an emitted dose containing particles with the greatest likelihood of lung deposition. This internal force is generated by the interaction between the user’s inhalation flow and the resistance of the DPI. Traditional compendial in vitro methods of measuring dose emission use a vacuum pump to simulate inhalation. We have adapted this in vitro method by replacing the square wave inhalation profile generated by a vacuum pump with the inhalation profiles of patients using an empty DPI. This method enables accurate assessment of the actual dose they would have inhaled. Effective use of DPIs depends on adequate powder deaggregation to aerosolize the drug with a high fine particle fraction (FPF), which facilitates adequate deposition of the drug in the lungs. Deaggregation of the drug depends on many factors, including the aerodynamic particle behavior of the formulation and the design of the inhaler. A typical patient’s inhalation profile (IP) generates a flow-versus-time profile that can be characterized by parameters such as the peak inhalation flow (PIF), the inhaled volume (Vin), and the initial acceleration of the inhalation maneuver (ACIM).The compendial method using vacuum pump exaggerate the acceleration rate and therefore is not representing the actual inhalation manoeuvre patients would receive in real life use. The results of our study on indacaterol Breezhaler® showed that the quantity and the quality of the emitted dose from the indacaterol Breezhaler® are dependent on the capability of a patient generating an optimal inhalation profile. Therefore, when using the device patients should be encouraged to inhale as fast as they can from the start of their inhalation and for as long as possible. The inspiratory parameters PIF, Vin and ACIM were acting together and it was difficult to distinguish the dominant factor in the overall dose emission from Indacaterol Breezhaler®. Recently, we altered the patients’ inhalation profiles by fixing two parameters and changing one at a time, the results showed that all inhalation parameters had an impact on the dose emission, dose emptying from the capsule/device in the order of PIF >Vin>ACIM. ACIM and Vin have almost an equal effect on the delivered dose (DD) and the fine particle dose FPD but the impact of the PIF was the most pronounced. This ex-vivo methodology provides a more realistic representation to the way patients use their inhalers and the type and quality of the dose they would receive in real life use.
Presentation Learning Outcome
• The presentation will provide the audience with an understanding on the correct use of dry powder inhalers to optimize drug delivery to the lungs
• The audience will gain an insight of the three important patient’s inhalation manoeuvre parameters to master the use of a dry powder inhaler.
• Importance of the patients’ profiles generated in-vivo and replayed using a breath simulator to assess the dose that patients would receive when using the inhaler.
