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The research article titled “Effect of Device Design and Formulation on the In Vitro Comparability for Multi-Unit Dose Dry Powder Inhalers” focuses on understanding the design space to achieve comparable in vitro performance of two multi-unit dose dry powder inhalers (DPIs)—Flixotide® Accuhaler® (reference product) and MultiHaler® (test product).
The study uses computational fluid dynamics (CFD) to model flow field, pressure drop, and particle trajectories within the test and reference DPI devices. Micronized fluticasone propionate (FP) is characterized to determine particle size distribution (PSD), specific surface area (SSA), and surface interfacial properties using cohesive-adhesive balance (CAB).
The research reveals that the pressure drop and airflow velocity in the MultiHaler® were greater than Accuhaler®. Two modified test devices (MOD MH 1 and MOD MH 2) were manufactured with the introduction of by-pass channels in the airflow path, which achieved comparable specific resistance and airflow path between the test and reference devices.
The study also investigates the influence of the device on aerosolization performance from that of the formulation. The reference product formulation was used to compare the in vitro performance of the test and reference DPI devices and assess the effect of device modifications on their in vitro comparability.
The research concludes that the application of CFD modelling and material characterization of formulation raw materials enabled the modification of device and formulation critical material attributes to create an in vitro comparable device/formulation system to the reference product.
