¹⁶¹Tb-Radiolabeling Service

The ¹⁶¹Tb-radiolabeling service offers an advanced solution for developing highly efficient theranostic agents for which the radionuclide is capable of functioning as a SPECT imager and a radiotherapeutic agent emitting therapeutically useful β- particles and Auger electrons. With a wealth of knowledge and sophisticated radiopharmaceutical development facilities, Alfa Cytology can provide high-purity ¹⁶¹Tb-labeled custom compounds, which will aid in the advancement of your oncology research.

Introduction to ¹⁶¹Tb Isotopes

Terbium-161 (¹⁶¹Tb) is an emerging radionuclide for targeted cancer therapy and for its unique decay spectrum. Its half-life is 6.89 days, during which it emits medium-energy beta particles for the therapy of larger tumors. It emits the number of low-energy Auger and conversion electrons, which is effective for the eradication of micrometastases. Its emission of gamma photons (mostly 49 and 75 keV) allows for SPECT imaging; thus, ¹⁶¹Tb is an exceptional theranostic agent for next-generation radiopharmaceuticals.

¹⁶¹Tb-Labeling for SPECT Imaging

Attaching the ¹⁶¹Tb is a novel approach to developing next-generation radiopharmaceuticals to help harness their full therapeutic potential. Targeting agents with attached ¹⁶¹Tb embark on a dual-action strategy by therapeutically treating larger tumor masses with medium-energy beta particles while simultaneously delivering a massive burst of Auger electrons for cytotoxicity to single cells and micrometastases. This powerful therapeutic profile, combined with gamma emissions for SPECT imaging, makes ¹⁶¹Tb-labeled compounds remarkable theranostic agents for cancer with precise targeting and elimination at high efficacy.

Fig.1 ¹⁶¹Tb development process. (FAVARETTO C, et al., 2023)

¹⁶¹Tb Radiopharmaceutical

Disclaimer: Alfa Cytology focuses on providing preclinical research services. This table is for information exchange purposes only. This table is not a treatment plan recommendation. For guidance on treatment options, please visit a regular hospital.

Our Services

Alfa Cytology offers a full range of specialized ¹⁶¹Tb radiolabeling services for antibodies, peptides, and other targeting molecules, advanced analytical ability, and radiopharmaceutical chemistry expertise. The dedicated platform of our company enables rapid development of next-generation radiotherapeutics employing high-purity, tailored conjugates.

Custom ¹⁶¹Tb Conjugation Service

Expertly conjugating the therapeutic radionuclide ¹⁶¹Tb to a diverse range of targeting molecules, including antibodies, peptides, and small-molecule agents.

Small-Molecule Radionuclide Conjugate (SMRC)

Antibody-Radionuclide Conjugate (ARC)

Peptide-Radionuclide Conjugate (PRC)

siRNA-Radionuclide Conjugate

Workflow for Developing ¹⁶¹Tb-Radiolabeled Small Molecule Conjugates

¹⁶¹Tb Custom Small Molecule Labeling

• Strategy & Reagent Selection: The first step includes a comprehensive consideration to establish the labeling strategy, choose the best chelator, and determine conjugation chemistry. In this stage, the selection of high-purity precursors and formulation buffers is finalized to optimally achieve the desired radiochemical yield.
• Ligand Conjugation & Characterization: With covalent conjugation of the chosen chelator to the targeting small molecule, using site-specific approaches to maintain bioactivity. The identity and purity of the conjugated precursor is then confirmed through extensive analytical characterization (e.g., HPLC, MS).
• Protocol Optimization: Systematically optimizes key factors in radiolabeling, such as the precursor concentration, pH, temperature, and contact time. Seeks to develop an efficient and reproducible method for ¹⁶¹Tb incorporation to the fullest degree.
• Custom Radiosynthesis: Conducts final radiosynthesis using high specific activity ¹⁶¹Tb under controlled and principled conditions. At this stage, the process is tailored according to clients' requirements, ensuring the consistency of the end product.

Purification & Quality Control

Every compound is verified for successful ¹⁶¹Tb incorporation after completing the labeling. Techniques, methods of scintillation counting, along with chromatography and mass spectrometry, are used to check the compound for isotopic labeling, as well as to analyze the purity and stability of the substance in order to ensure the compound is suitable for biological studies.

In Vitro Evaluation

In vitro tests are performed to evaluate the biological properties of the ¹⁶¹Tb-labeled radiopharmaceutical. This includes studying its interaction with target receptors, cellular uptake, metabolic stability, and other pharmacological properties.

In Vivo Evaluation

The first part of this important step involves quantitative biodistribution and pharmacokinetic (PK) studies in which the agent's uptake in various organs and its clearance rate from the body are painstakingly calculated. Subsequent to this, in relevant disease models, SPECT imaging is performed to demonstrate target engagement and unequivocally prove the agent's diagnostic value in vivo through blocking experiments.

Applications of ¹⁶¹Tb-Radiolabeling

Harnessing the unique theranostic potential of Terbium-161 to visualize and eliminate cancer cells with unparalleled precision.

At Alfa Cytology, we can offer reliable, robust ¹⁶¹Tb-radiolabeling services due to the competence of our dedicated team and our experience. Contact us about your project, and we can offer an individualized experimental design to satisfy your scientific objectives.

Reference

1. FAVARETTO C, GRUNDLER P V, TALIP Z, et al. (¹⁶¹)Tb-DOTATOC Production Using a Fully Automated Disposable Cassette System: A First Step Toward the Introduction of (¹⁶¹)Tb into the Clinic [J]. Journal of nuclear medicine: official publication, Society of Nuclear Medicine, 2023, 64(7): 1138-44.

For research use only. Not intended for any clinical use.