Best Practices for Developing Dry Powder Inhaler Combination Drug-Device Products

Dry powder inhalers (DPIs) are combination drug-device products in which a powdered drug product is contained in a capsule or other format and is released when activated by the patient breathing in through the device. Pharmaceutical Technology spoke with Marco Laackmann, director of Inhalation Technology at Harro Höfliger, which provides filling, assembling, and packaging machinery for inhalation and other drug products and systems, about some of the challenges for developing and manufacturing DPIs.

Choosing a DPI technology

PharmTech: DPIs come in different formats, such as hard capsules, blisters, cartridges, or disks-what are some of the key facets to review when deciding which to use? 

Laackmann (Harro Höfliger):Device selection is key in every DPI project. It is said that the device selection is first. So, within a project, a DPI selection process must review the pros and cons with regard to human factors, cost, complexity, and time to market. Simpler DPIs, such as a capsule inhaler, can use standard filling and handling equipment. In this case, the product differentiation and entrance barriers for generic competition are low. With increasing complexity of a device, the manufacturing process starts getting complex. However, such devices offer competitive advantages (patient adherence and compliance) and are more difficult to make as they often use bespoke equipment and processes.

Development challenges

PharmTech: What are some of the considerations for how powder characteristics and powder handling affect the combination drug-device product? 

Laackmann (Harro Höfliger): Powder dosing systems can affect powder properties. The handling of powder might change pharmaceutical product characteristics. During development, it is important to consider the scale-up of powder dosing technologies. Any change in late development phases may create the need for additional process development or reformulation efforts to meet the pharmaceutical target profile of a drug product.

We see an increasing trend towards particle engineering. Powder from various types of spray drying or other particle generating processes are creating new types of DPI powders. They are completely different in rheology and physical properties and mechanical robustness to survive forces (e.g., pressure, shear, etc.) compared with what is historically known about lactose-based DPI powders. This trend is being addressed with regard to improved and modified powder dosing technologies as well as in-depth process development to understand limitations and process windows of existing powder dosing technologies.

PharmTech: What are some of the challenges with scaling from lab to commercial scale?

Laackmann (Harro Höfliger): Scale-up might involve different powder handling technologies. The way of powder processing, however, should not change. So, the major challenge is the selection of a powder dosing application that assures similarity in the metering technology for laboratory work as well as for commercial production lines. Often, in an early project phase, this selection process is focusing on the funding and cost without considering future needs. [Another] key challenge is the allocation of know-how, powder expertise, and technical support to develop products suitable for commercial-scale manufacturing.