Physicochemical properties of Rituximab

In order to demonstrate physicochemical comparability of a recombinant protein medicament as a drug substance (Active Pharmaceutical Ingredient or API), such as Rituximab, one must first choose suitable orthogonal analytical methods that selectively provide information regarding the identity and heterogeneity of the molecule. The application of these methods in the investigation of process-derived variability of the reference molecule can yield valuable information to establish comparability criteria. This could become the basis to determine the critical physicochemical attributes that should be verified by relevant in-process controls and batch release criteria. In this paper we show the determination and analysis of relevant attributes from two different proposed biosimilars. We show differences in Reditux proposed Rituximab biosimilar, mainly in charge heterogeneity patterns, whereas no major differences were found for Kikuzubam as related to the Mabthera reference batches. The detected differences are an indication of the capability of several analytical methods to show relevant physicochemical attributes during comparability exercises.