A study of protein aggregation processes using Dynamic Light Scattering : Validation of the technique and experimental trial with an active pharmaceutical ingredient

Abstract: Protein pharmaceuticals is one of the fastest growing class of therapeutics today. However, they pose a lot of challenges in production lines due to their poor stability. Protein aggregation is one of the most common results of protein instability and is a risk factor regarding the quality of therapeutics. This master thesis at RISE focused on validating the techniques Dynamic Light Scattering (DLS) and multi angle DLS (MADLS) with respect to detection of aggregation. The model protein B-lactoglobulin was used to assess the robustness and accuracy of DLS. A comparison between two instruments from Malvern, Zetasizer Nano (2006) and Zetasizer Ultra (2018) was done with respect to DLS. It was determined that they were in many ways equivalent, but the newer model Ultra was favourable due to reduced noise and its ability to detect a lower concentration of aggregates. MADLS produced more precise results which is reflected in narrower distributions and has a higher sensitivity than DLS with regards to separating particles near in size. Both techniques proved sensitive enough to differentiate between aggregates and native protein. Experimental trials were performed with an active pharmaceutical ingredient, API. The experimental trials with the API aimed to investigate what conditions and surface-interfaces that might pose a risk for aggregation. Despite efforts put in creating an environment where aggregation could be monitored, aggregation could not be established. Measurements with the API generated less reliable results due to noisy data and a lack of reproducibility between individual measurements.