Development of a Freeze-Dried Bevacizumab Kit for 99m Tc Radiolabeling and Preclinical Evaluation In Vitro and in Normal Mice
Thi Khanh Giang Nguyen, Thi Ngoc Nguyen, Thanh Binh Nguyen, Ho Hong Quang Dang, Thu Minh Chau Nguyen, Dang Khoa Nguyen, Thanh Nhan Nguyen, Tran Quang Thai Vo, Trung Tin Dang, Ngoc Bao Nam Dinh, Thanh Minh Pham, Thi Thu NguyenBackground:
Bevacizumab, a humanized monoclonal antibody targeting vascular endothelial growth factor (VEGF), was lyophilized and radiolabeled with
99m
Tc for tumor-targeted imaging. In this study, a freeze-dried kit was developed, the formulation was optimized, and the radiolabeled bevacizumab was evaluated
Methods:
The preparation process was optimized by investigating pH, temperature, time, and stabilizers. The radiochemical purity (RCP) and immunoreactivity of the lyophilized antibody were determined and confirmed by specific binding to VEGF immobilized on Ni–NTA agarose. Preclinical evaluations included binding assays on three human cancer cell lines (A-549, MCF-7, and HT-29), in which binding affinity (K d ) and maximum binding capacity (B max ) were calculated. Biodistribution studies were performed in normal mice.
Results:
The optimized kit contained 2.0 mg bevacizumab per vial in phosphate buffer at pH 7.5, ensuring reproducible reconstitution and high labeling efficiency. Quality control demonstrated RCP >97% and
Conclusions:
The freeze-dried bevacizumab enables convenient 99m Tc radiolabeling, providing a preclinical proof-of-concept supporting further development as a tumor imaging-agent.