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Radionuclide-Small Molecule Conjugation Service

Small molecule-based RDC (Radionuclide Drug Conjugate), a new type of drug for cancer treatment, has received a lot of attention. The conjugation of radionuclide-small molecule is a very professional process.

As a top CRO company, Rdcthera can provide a high-quality radionuclide-small molecule conjugation service for you.

Small Molecule Based RDC

The most widely developed small molecule-based RDC is the one targeting the PSMA (Prostate-Specific Membrane Antigen), a type-II transmembrane glycoprotein with several enzymatic functions overexpressed in prostate cancer. Prostate cancer is the second most prevalent type of cancer among men worldwide. The PSMA-directed radiopharmaceuticals are now used extensively for diagnostic imaging and treatment.

Fig.1 Chemical structure of two small molecule based RDC examples.Fig.1 Chemical structure of two small molecule based RDC examples.
(Debnath, S., et al., 2022, International journal of molecular sciences)

Overview of Radionuclide-Small Molecule Conjugation

Conjugation is a chemical strategy to form a stable covalent link between two molecules/polymers or biomolecules/biopolymers together. With a connection between the targeting molecule and a cargo, effective targeted therapy for cancer becomes possible. A myriad of conjugated complexes for cancer treatment, including lung cancer, colorectal cancer, breast cancer, multiple myeloma, lymphoma, prostate cancer, and melanoma are newly discovered.

The chemical reaction condition for the conjugation process of small molecule and radionuclide-chelator complex is quite demanding and very sensitive to the temperature, pH, catalyst, and substrate concentration of the reaction. The most common chemical bonds in radionuclide-small molecule conjugation are the disulfide bond and amide bond by adding sulfhydryl or amine groups in a small molecule during synthesis.

Fig.2 Test tubes in the RDC development process.

Our Service

In this case, our conjugation service is to bind the radionuclide-chelator complex to target small molecules through a linker to provide a solution for selective and targeted delivery of bifunctional radioactive particles. This radiolabeled small molecule can conduct both diagnostic imaging and cancer treatment at once.

  • Radionuclide-Small Molecule Conjugation Service
  • Rdcthera can provide different kinds of conjugation strategies, such as forming disulfide bondamide bond and so on. The conjugation process of a radionuclide-small molecule requires consideration of many factors.

  • Different Components

With different radionuclides, chelators, and linkers, the conjugation condition needs to be adjusted and the metabolism and pharmacokinetics of the final product will be changed.

  • pH and Temperature

The synthesis of small molecule-based RDC could be optimized by adjustment of pH and temperature to subsequently reduce side products.

  • Other Parameters

Besides, a large number of additional aspects need to be considered, including time and procedure of production process and exposure during production.

  • RCP (Radiochemical Purity) Evaluation
  • To ensure the high quality of our RDC products, before the product delivery, ascending chromatography, SPE (Solid-Phase Extraction), and RP-HPLC (Reversed-Phase High-Performance Liquid Chromatography) will be conducted.

  • Ascending Chromatography
    An analytical method for chemicals or substances separation.
  • SPE
    An extractive technique to separate, concentrate, and purify the interested samples from a wide variety in a mixture.
    An extractive technique in analytical chemistry to isolate, identify, and quantify interested samples in a mixture.

Project Workflow

Fig.3 Project Workflow.

Why Choose Us

Radioactive icons.

Focused on RDC research for decades, Rdcthera is capable to provide high-quality and cost-effective RDC conjugation service for your special RDC project with the best scheme design and conjugation service to meet your demand.

Conical bottle icon.

Rdcthera can provide all kinds of services through the whole RDC development process, including custom conjugation services according to your interests and lateral RDC analysis services.

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With an experienced research team and top-notched equipment, Rdcthera enable seamless scaling of RDC products from drug production to preclinical development. Collaborate across functional teams to promote your RDC development.

We are eager to share our experience and technology with you to support your RDC development project. Please contact us for more information.


  1. Debnath, S., Zhou, N., McLaughlin, M., Rice, S., Pillai, A. K., Hao, G., & Sun, X. (2022). PSMA-Targeting Imaging and Theranostic Agents—Current Status and Future Perspective. International journal of molecular sciences, 23(3), 1158.
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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