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Lactose Specifications: Supplier and Process Defined Properties vs. Surface Characteristics Controlled and Specified In-house

Young PM.

Respiratory Drug Delivery 2016. Volume 1, 2016: 165-174.

Abstract:

Understanding the physicochemical properties of lactose is an essential aspect of dry powder inhaler (DPI) research and development. Furthermore, routine monitoring of lactose batches during a product’s lifespan is key to ensuring consistency in aerosol performance and dosing. There are numerous physicochemical tools available to characterize lactose, however laser diffraction derived particle size measurements, bulk, and tapped density, as well as surface area, via gas adsorption, are the most common data provided by the lactose supplier. While these descriptors provide valuable information to a formulator, there is no direct correlation between size or surface area and aerosol properties, and variations in performance can be seen between lactose batches that appear similar based upon these parameters. Thus, additional techniques may be required. Key measurements that can be studied include surface topography, surface energy, rheology, and presence of amorphous content. This review looks at recent techniques used to measure these properties and takes a critical look at the results that can be produced and how useful these are in providing valuable information for the formulation scientist during DPI development.