99mTc-Labeled Cefixime for Targeted Imaging of Infections: Preclinical Evaluation and Potential in Postpartum Women.

Introduction: Targeted infection imaging is crucial for accurate diagnosis in postpartum women. This project uses 99mTc-labeled cefixime to develop a radiopharmaceutical for detecting, distinguishing, and treating infections and abscesses in women.

Method: Technetium (TcO4-) chelated with cefixime, reduced by stannous chloride, confirmed via thin-layer chromatography. Mice injected with the labeled compound showed pyrogenicity and stability tests at one, two, and three hours. Bio distribution and SPECT (CT) imaging revealed in vivo aspects post-injection.

Results: Radiolabeling achieved over 95% technetium binding to cefixime, as shown by ITLC with acetone, demonstrating high labeling efficiency. The labeled molecule remained stable for three hours, providing an adequate imaging window. SEM analysis confirmed drug presence on the complex, IR spectroscopy verified cefixime-tracer bond formation, and HPLC quantified radiolabeling yield.

Discussion: Bio distribution studies revealed that radiolabeled cefixime accumulated mainly in the kidney and bladder (31.38%) and liver (30.1%), indicating renal and hepatic clearance pathways. Moderate uptake appeared in the small and large intestines (24.6%), whereas lower distribution was observed in the lungs (4.3%), heart (4.1%), stomach, and spleen (5.4%). SPECT/CT imaging demonstrated drug accumulation in infected thigh tissues, distinguishing them from inflamed sites, underscoring its diagnostic potential for differentiating infectious from inflammatory conditions. The approach shows promise for clinical translation in postpartum infection management and beyond.

Conclusion: Cefixime, labeled with 99mTc, accurately detects rodent infections via scanning. Its potential extends to distinguishing healthy and malignant cells in human plasma, indicating promise in medical diagnostics, including identifying unknown-etiologic pyrexia in post-partum women.