Structural and thermal stability assessment of repackaged bevacizumab using RT-PCR-based differential scanning fluorimetry and intrinsic fluorescence spectroscopy

: IntroductionBevacizumab is a humanized monoclonal anti-VEGF antibody widely used in oncology and ophthalmology for the treatment of age-related macular degeneration and diabetic macular edema. Its intravitreal administration requires galenic repackaging, raising concerns regarding physicochemical stability and sterility assurance during storage. This study evaluated the structural and thermal stability of repackaged bevacizumab stored at 4 °C for up to four weeks.MethodsStability was assessed using intrinsic fluorescence spectroscopy and differential scanning fluorimetry (DSF) performed on a real-time PCR platform. Structural integrity was monitored through fluorescence emission spectra, while thermal stability was determined by melting temperature (Tm) analysis over time.ResultsIntrinsic fluorescence showed a constant emission maximum at 338 nm throughout the storage period, indicating preservation of the tertiary structure. DSF analysis demonstrated stable thermal unfolding profiles, with no significant variation in Tm values between baseline (67.4 ± 0.3 °C) and four weeks (67.2 ± 0.4 °C; p > 0.05).ConclusionsRepackaged bevacizumab maintained structural integrity and thermal stability for up to four weeks under refrigerated storage conditions. These findings support refrigerated batch preparation under the tested conditions and highlight RT-PCR-based DSF as a practical quality-control tool for hospital pharmacy settings.