Similarity assessment of charge variants for bevacizumab biosimilar formulations using imaged capillary isoelectric focusing
The imaged capillary isoelectric focusing method was developed and validated for charge variant analysis of the bevacizumab innovator product and its biosimilar formulations (N = 2). The optimized method consists of; 4 M urea, 2.0 mM iminodiacetic acid, 0.35% m/v methylcellulose, 5.0 mM L-arginine, 4.0% v/v carrier ampholytes (narrow-range isoelectric point 5–8 and 8–10.5 with ratio of 1:3), 60 mM sodium hydroxide and 30 mM phosphoric acid as catholyte and anolyte solutions. The bevacizumab innovator and biosimilars formulations were observed with two acidic peaks followed by the main peak and two basic peaks. The validation of the developed method was done by performing intraday (n = 6) and interday (n = 9) precision studies with observed RSD < 2.0%. The limit of detection and limit of quantification of the developed method was found to be 0.016 and 0.048 mg mL−1. The charge variant profiles observed for innovator and biosimilar formulations (N = 2) were then applied for statistical comparison using one-way ANOVA, Dunnett’s test. This study can serve as a reference to biosimilar manufacturers and startups on how to assess the charge variant profiles of bevacizumab during the manufacturing process.