Title : Impact of inhalation manoeuvre parameters on drug delivery to the Lungs from dry powder inhalers in-vitro and Ex-vivo
Inhaled therapy plays an important role in the management of airway diseases such as, asthma and chronic obstructive pulmonary disease (COPD). Peak inhalation flow has been considered for so many years by the inhalation scientists as the most important parameter governing drug delivery to the lungs from DPIs, however, many patients especially those with low lung capacity are unable to generate sufficient inhalation flow to deaggregate the powder formulation to get most of the dose into their lungs. In addition to the peak inhalation flow (MIF), this presentation will focus on other inhalation parameters such the inhaled volume (Vin) and the acceleration rate of the air flow at the start of the inhalation manoeuvre (ACIM) and to investigate their impact on the dose emission and aerodynamic characteristics from two inhaler devices (low resistance: Ombrez Breezhaler and high resistance device: Easyhaler).
Traditionally, the in-vitro total emitted dose (TED) and its particle size distribution via a DPI is measured using standard pharmacopoeial methods and is widely accepted by the regulatory authorities. The method involves simulating an inhalation profile through a dry powder inhaler (DPI) using a vacuum pump to emit a dose and collect it into a cascade impactor. The measured particle size distributions represent particle deposition into different zones of the lungs. Humans cannot replicate the square wave generated by a vacuum pump; nor can the majority of patients achieve the pharmacopoeia-recommended inhalation parameters (4 KPa pressure drop and 4 Litres inhaled volume). These limitations are becoming more problematic as the use of DPIs are extended to, for example: paediatric, who do not have the lung capacity of a healthy adult. In this presentation we will discuss an Ex-vivo method that replaces the vacuum pump used in pharmacopoeia methods with a patient inhalation profile to provide information on the TED that the patient would have inhaled in real life.
Audience take away:
The difference between different dry powder inhalers (DPIs) and how the design of a DPI device affects drug delivery to the lungs.
should we look for a threshold inhalation flow to deaggregate the powder formulation or the peak inhalation flow when choosing an inhaler device?
Understand the important inhalation manoeuvre parameters to maximize drug delivery to the lungs, especially for patients with low lung capacity.
Understand how to use a DPI more efficiently to get most of the inhaled dose into the lungs.
In case patient cannot generate a high flow rate, they should be encouraged to prolong their inhalation time or inhale twice to empty the dose.
Introducing the audience to an Ex-vivo method using patient inhalation profile that replaces the vacuum pump used in pharmacopoeia methods.