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Physiochemical Evaluation Services of Radioconjugates

Welcome to Rdcthera, a leading preclinical CRO in comprehensive radiopharmaceutical services. We specialize in high-quality physiochemical evaluation services for radioconjugates. We strive to offer our clients in the pharmaceutical and biotechnology sectors all-embracing services that assure the efficacy, safety, and regulatory compliance of radioconjugates.


Radioconjugates are complex molecules formed through the attachment of a radioactive isotope to a targeting vector such as an antibody, peptide, or small molecule. Such conjugates deliver radiation directly to specific cells or tissues and, therefore, are valuable for both diagnostic imaging and targeted radionuclide therapy. Precise targeting and therapeutic efficacy of radioconjugates strongly depend on physiochemical properties; thorough evaluation is needed to guarantee optimal performance.

Fig 1. Schematic representation of stability study for radioimmunoconjugates.Fig. 1. [225 Ac]Ac-Macropa-GC33 and [225 Ac]Ac-Macropa-IgG1 are stable in human serum and PBS. (Bell MM, et al., 2020)

Our Solutions

Rdcthera offers physicochemical analysis services for the stability, lipophilicity, immunoreactivity, and radiochemical purity of radioconjugates. These details are very critical in understanding the behavior of these compounds in biological systems, predicting in vivo performance, and ultimately determining safety and efficacy. Rigorous physicochemical characterization helps optimize formulations to improve the therapeutic index and meet regulatory requirements.

At Rdcthera, comprehensive stability testing is conducted under various environmental conditions to assess the degradation pathways of radioconjugates and identify potential instabilities. We perform accelerated and real-time stability studies, as well as stress testing, to provide you with a comprehensive stability profile of your radioconjugate products.

A key parameter determining biodistribution and pharmacokinetics in drug radioconjugates is lipophilicity, the affinity of a compound for lipids relative to aqueous phases. These services include the determination of partition coefficients (log P) and distribution coefficients (log D) using modern techniques. These studies guide in predicting in vivo behavior of the radioconjugate, formulation strategies, and optimizing therapeutic efficacy.

Since these coupling procedures can have a deleterious effect on the antibody, further quality control procedures have to be used to identify the most important characteristics of the radioimmunoconjugate. Our services in immunoreactivity assays offer a detailed quantitative and qualitative determination of the binding affinity and specificity of radioimmunoconjugates. We apply various approaches to ensure that the results are accurate and reliable.

Radiochemical purity (RCP) reflects the fraction of the radioconjugate in the desired chemical form. High RCP is critical to ensuring the safety and efficacy of a radioconjugate. At Rdcthera, we conduct thorough assessments of RCP using high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), and radio-electrophoresis. Our methodologies are exact, which guarantees the accurate determination of RCP in support of quality control and regulatory approval for your radioconjugate.


Our evaluation services are applicable to a variety of radiopharmaceuticals used in diagnostic imaging or targeted radionuclide therapy, supporting development and optimization in oncology, cardiology, neurology, and other therapeutic areas. By providing comprehensive physicochemical data, we help our clients advance their radioconjugate products from research and development through to preclinical trials.

For more information about our services or to discuss your specific project needs, please contact us. We look forward to partnering with you to advance the development of your radiopharmaceutical products.


  1. Bell MM, Gutsche NT, King AP, et al. (2020). Glypican-3-Targeted Alpha Particle Therapy for Hepatocellular Carcinoma. Molecules. 26(1):4.
For research use only. Not intended for any clinical use.

Rdcthera RDC

Rdcthera offers efficient, customized, and professional R&D services related to radionuclide drug conjugates.

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