Quantification, Microbial Contamination, Physico-chemical Stability of Repackaged Bevacizumab Stored Under Different Conditions

In this work, the stability of Bevacizumab (Avastin®) repackaged in individual 1 mL single-use syringes and stored at different conditions was assessed. Bevacizumab repackaged in single-use syringes results from the off-label use of the drug as an intravitreal agent in the treatment of retinal diseases. Bevacizumab stability was assessed by assaying the anti-VEGF activity using an indirect ELISA method and a Dynamic Light Scattering study. The thermal stability of the drug was also studied by calorimetric analysis, aimed to evaluate thermodynamic parameters associated to the thermal unfolding process. Furthermore, microbiological and fungal tests on the Bevacizumab syringes were performed. As a result, a significant decrease of the anti-VEGF activity was detected when syringes were exposed to UV light at a temperature of 37°C. Under these conditions, the Dynamic Light Scattering study showed an increase of the average size of Bevacizumab; probably due to aggregation. In conclusion, Bevacizumab stability, when stored under different conditions, was assessed considering three different aspects: anti-VEGF activity, microbial contamination and physico-chemical properties. Bevacizumab was found to be stable, under sterile conditions, for 3 months at 4°C and for 7 days at room temperature, exposed to indirect light sources, while a brief exposure of the drug to direct UV radiation proved detrimental to drug stability.