Dilution, formulation conditions do not impact in-use stability of rituximab biosimilars
The in-use stability of rituximab biosimilar Rixathon/Riximyo is not affected by dilution and formulation conditions needed for intravenous infusion even under worst case condition in terms of product shelf life, temperature excursion, light exposure, dilution factor and infusion bag storage time over a period of 31 days, according to biological and physicochemical analyses of a recent study.
The investigators assessed the in-use biological and physicochemical stability of the Sandoz rituximab biosimilar, marketed under the trade names Rixathon and Riximyo in the European Union, upon preparation for intravenous infusion. They exposed three batches of Rixathon/Riximyo in the final month of the samples’ 36-month shelf life to room temperature and light for 14 days to recapitulate a major temperature excursion.
The biosimilars were diluted to the lowest allowable concentration of 1 mg/mL in 0.9% sodium chloride (NaCl) solution in either polypropylene or polyethylene infusion bags and stored for 14 or 30 days at 5±3°C. This was followed by an additional 24 hours at room temperature to simulate product handling.
Size exclusion and ion exchange chromatography, nonreducing SDS capillary electrophoresis, peptide mapping and complement-dependent cytotoxicity assay were used to analyse samples stored in infusion bags and to examine biological and physicochemical stability.
Analysis revealed no change over a 31-day period in molecular weight and charge variants, as well as deamidation, oxidation, overall composition or potency for Rixathon/Riximyo diluted to the lowest allowable concentration in 0.9% NaCl in either polypropylene or polyethylene infusion bags.