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Quantification of Physical Robustness
Lyophilisation, also known as freeze drying, has long been the preferred method for the stabilisation of labile drugs, biotherapeutics, and vaccines, considered a more gentle process next to traditional drying methods (such as spray, oven, and fluidised bed drying). Lyophilisation also offers an opportunity to produce material with low moisture content and high surface area, allowing the possibility of long-term stability at ambient temperatures and rapid reconstitution prior to use. However, lyophilised products can undergo physical breakup during transportation and handling due to their low density, sometimes becoming fragmented and powdery, which, in turn, impacts end-user perception of product quality as well as the time taken for reconstitution.
Standard quantitative tests for critical quality attributes (CQAs), such as residual moisture (or solvent) levels, activity, thermal properties, and stability, are numerous, and most manufacturers would agree that the cosmetic appearance of the product is also important. However, in the past, there has been no method to quantify this aspect. Techniques such as scanning electron microscopy can contribute an idea of morphology at the microscopic level, while gas adsorption methods even further provide an estimate of specific surface area and mean pore diameter of a lyophile; however, it can legitimately be argued that the sample preparation process itself, for either of these measurements, can lead to changes in the morphology of the material under test. Rheometers and tensile testing devices on the market are generally designed for application to less flexible and higher-density materials than lyophiles, and with some degree of sample preparation required.Dr Kevin R Ward, Joshua Robinson, and Thomas B Codd at Biopharma Group (October 2019)
Keywords: Lyophilisation, BioPharma, Freeze-drying, CQAs Biotherapeutics, Stabilisation, Quantification, Methods, BioPharma Group, Samedan ltd
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