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38 Pharmaceutical Technology APIs, EXCIPIENTS, AND MANUFACTURING eBOOK 2021 P h a r mTe c h . c o m Manufacturing tions caused by viruses, fungi, and bacteria, as well as airborne pathogens such as tuberculosis, influenza, Ebola, measles, and SARS-CoV-2. Perhaps the biggest challenge for CDMOs in spray drying is being able to scale up from bench/lab spray- ers to [current good manufacturing practice] CGMP commercial scale, and understanding how the tem- perature, flow rate, spray position, droplet size, and drying time inf luence particle size and [how the] electrostatic charge of the particle needs to be opti- mized to ensure efficient particle aerosolization in a drug delivery device. Developing inhaled drug prod- ucts will always be more technically challenging than for other more conventional routes of administration. However, advances in both the knowledge of the physicochemical properties of inhaled drug particles, and manufacturing knowhow, can help to accelerate the development of more molecules for inhalation. Heath and Hirst (Recipharm): Many existing drugs are low molecular weight, crystalline substances, which can be micronized into a targeted size suitable for in- halation product development. These drugs are stable and well understood, and they are relatively low-dose products in the range of micrograms. Many new drugs being developed, however, are complex biomolecules, which have issues with physical stability and are often delivered in higher doses owing to their low potency. A recognition of new global pressures towards more sustainable products is driving the investigation into alternative propellants in pressurized MDIs (pMDIs), providing new potential formulation opportunities. A suspension pMDI can be prone to issues with physical stability, where the suspended crystals grow and alter the performance of the product over time. Particle en- gineering technologies offer unique opportunities to protect against this detrimental effect as well as offer- ing enhanced dispersibility and targeted delivery of the drug to the lung. In the DPI world, these same particle engineering technologies can again reduce the inter- action between powder particulates, allowing a freer flowing, easily dispersed powder, which can be tuned to a specific size distribution and appearance and ulti- mately deliver the drug to the correct area of the lungs. The infrastructure to handle these complex drug products successfully is significant, with health and safety requirements, environmental conditions (temperature and humidity), and use of solvents to consider along with the physical handling of these free-flowing powders when it comes to device filling. These may pose a challenge for drug developers, and CDMOs can bring their expertise and facilities to the forefront in this new wave of challenging inhala- tion drug development. For biologics, such as proteins, peptides, nucleic acids, and bacteriophages, we are seeing new meth- ods to manufacture drug products. Inhaled biolog- ics have high specificity that may reduce 'off target' side effects. These new inhaled treatments may be for local (lung diseases) and also systemic delivery for the treatment of other illnesses, due to the non- invasive method of delivery and rapid absorption. Munro (Vectura): There is huge interest in the develop- ment of inhaled biologic products for the treatment of niche diseases or the more intractable areas of the major respiratory diseases such as asthma and [chronic obstructive pulmonary disease] (COPD). In turn, this "Inhaled particle engineering has paved the way for drugs to be developed to tackle more complex diseases." —Carolyn Berg, Catalent