New Process Approach for Metered-Dose Inhalers: Dry-Filling

Metered-dose inhalers (MDIs) are inhalation devices that use a propellant to deliver a precisely measured dose of medication to the respiratory tract with each actuation. With Dry-Filling, Harro Höfliger introduces a new process for manufacturing the cans used in these inhalers.

The development is driven by fundamental changes in the propellants used in MDI products. New substances with lower global warming potential are reshaping safety requirements and production concepts. In response, Harro Höfliger and Pharmatec Solutions Ltd. have developed Dry-Filling. Complementing established MDI filling technologies, it creates additional opportunities for designing future production concepts.

Unlike conventional processes, Dry-Filling eliminates the need to prepare an API-propellant mixture. Instead, the process consists of three clearly separated steps: dosing the active ingredient into the open can, sealing the can by crimping, and subsequently filling the propellant through the valve. As a result, propellant handling during the early stages of production is significantly reduced, enabling smaller ATEX zones and lower explosion protection requirements within the manufacturing environment.

Dry-Filling also eliminates typical production bottlenecks. Without upstream mixing steps, batch sizes are no longer constrained by the capacity of mixing vessels. Cleaning requirements are reduced as well. This helps minimize downtime and improve overall equipment effectiveness (OEE).

Laboratory-scale equipment is already available for evaluating the process. The resulting data can be used to transfer the concept to production-scale manufacturing lines.

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