Systematic Development of an Inhaler Device for the Use in Horses: The EquiHaler®
Herbert Wachtel1, Marcus Rahmel1 Guido Endert2 & Benjamin Franzmann3
1 Boehringer Ingelheim Pharma GmbH & Co KG, Binger Strasse 173, 55216 Ingelheim, Germany
2 DESIGNquadrat GbR, Schmiedhofsweg 1, 50769 Köln, Germany
3 Boehringer Ingelheim Vetmedica GmbH, Binger Strasse 173, 55216 Ingelheim, Germany
Soft Mist Inhalers™, like the Respimat® SMI™, are officially called non-pressurized metered dose inhalers and provide unique medicinal aerosol generated features such as: a slowly moving aerosol cloud, a small droplet particle size, high fine particle fractions, as well as an intuitive user interface. A high medical need for an advanced aerosol treatment has been identified in horses. Based on the idea that Respimat® technology should be available across species, equine feasibility studies were conducted by Boehringer Ingelheim Vetmedica GmbH. Considering the upper airway geometry of horses and their typical breathing patterns as well as the user habits, a novel and innovative device has been built around the functional core units of the Respimat®. A set of relevant interfaces and characteristics has been defined, these include: the nostril adapter (connecting the nostril of the horse with the inhaler containing a breath indicator), and the handle with a dual-functional lever enabling single hand operation by the user. Here we describe the interdisciplinary cooperation of the design team, the resolution for the equine anatomical puzzle, aerosol science, human operational factors, and last but not least the coordination challenge of treating an animal. As a result of these studies, the EquiHaler® was designed to give relief to many suffering horses. In this inhaler an ethanolic solution, containing the 3rd generation corticosteroid ciclesonide, is used to treat clinical symptoms associated with equine asthma, formerly known as RAO (recurrent airway obstruction) and SPAOPD (summer pasture associated pulmonary disease). The combination of EquiHaler® and the ethanolic formulation generates an extra fine aerosol characterized by an adaptable therapeutic dose of 2.7 mg (8 actuations) and a mass median aerodynamic diameter of 1.5 µm, depending on the operating conditions of the impactor.