Advanced microscopy techniques to assess solid-state properties of inhalation medicines

Abstract

Efficient control and characterisation of the physico-chemical properties of active pharmaceutical ingredients (APIs) and excipients for orally inhaled drug products (OIDPs) are critical to successful product development. Control and reduction of risk require the introduction of a material science based approach to product development and the use of advanced analytical tools in understanding how the solid-state properties of the input materials influence structure and product functionality. The key issues to be addressed, at a microscopic scale, are understanding how the critical quality attributes of input materials influence surface, interfacial and particulate interactions within OIDPs. This review offers an in-depth discussion on the use of advanced microscopy techniques in characterising of the solid-state properties of particulate materials for OIDPs. The review covers the fundamental principles of the techniques, instrumentation types, data interpretation and specific applications in relation to the product development of OIDPs.

WITHDRAWN: 3D characterisation of dry powder inhaler formulations: Developing X-ray micro computed tomography approaches

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Insights into the multifaceted application of microscopic techniques in plant tissue culture systems

“…Basically, microscopy involves the use of microscopes to enlarge samples or objects which originally are beyond the resolution of the human eye (Shur and Price 2012; Thomasson and Macnaughtan 2013). As an indication of the great importance and value of microscopy, it remains a popular and vital tool with a wide range of applications in basic and applied sciences (Tranfield and Walker 2013;Zumbusch et al 2013;El-Bakry and Sheehan 2014;Whited and Park 2014) as well as in the medical and material engineering fields (Torrealba and Carrasco 2004;Shur and Price 2012;De Boer et al 2013;Juszczyk et al 2013). These aforementioned publications also provide excellent reviews highlighting the trends and current updates related to the specifics and significance of microscopy in these various fields.…”

CARS microscopy as a tool for studying the distribution of micronised drugs in adhesive mixtures for inhalation

“…Scanning electron microscopy (SEM) may be considered the standard imaging technique used for the characterisation of the appearance of adhesive mixtures. It has proven to be valuable in studying the morphology of particles in adhesive mixtures for inhalation because of its high resolution . However, with this nonchemical‐specific imaging technique, drug particles are difficult to distinguish from fine lactose excipient particles (fines), which are always present in the formulation.…”

“…It has proven to be valuable in studying the morphology of particles in adhesive mixtures for inhalation because of its high resolution. [20] However, with this nonchemical-specific imaging technique, drug particles are difficult to distinguish from fine lactose excipient particles (fines), which are always present in the formulation. To date, it has thus not been possible to accurately assess the composition of agglomerates or the spatial distribution of the drug over the carrier surface.…”