¹⁸⁸Re-Radiolabeling Service

¹⁸⁸Re-radiolabeling employs generator-produced radionuclide Rhenium-188 to construct theranostic agents which provide therapy with high-energy beta particles, coupled with real-time, high-resolution, SPECT imaging. Alfa Cytology provides comprehensive development for ¹⁸⁸Re-conjugates and ¹⁸⁸Re-based theranostic agents for the preclinical stages, leveraging its deep expertise in rhenium and technetium-based radiochemistry.

Introduction to ¹⁸⁸Re Isotopes

Rhenium-188 (¹⁸⁸Re) is a highly attractive theranostic radionuclide available from a long-lived Tungsten-188/Rhenium-188 (¹⁸⁸W/¹⁸⁸Re) generator system. It has a half-life of 17 hours, during which it produces a beta particle that is capable of treating larger tumors. It additionally emits a 155 keV gamma photon, which is an ideal candidate for quantitative SPECT imaging. Its ability to treat and image is even more improved by its chemical similarity to Technetium-99m, which allows the vast knowledge of Tc-based chelation chemistry to be used. Hence, the ability of on-demand production and powerful beta therapy, and SPECT imaging, together, make ¹⁸⁸Re a distinguished radioisotope for versatile radiotherapeutics.

¹⁸⁸Re-Labeling for SPEET Imaging

Rhenium-188 (¹⁸⁸Re) labeling is a powerful methodology for creating agents for SPECT imaging. It offers a 155 keV gamma photon, which a standard gamma camera can capture, allowing for high-quality imaging. The 17-hour half-life of this isotope is ideal for tracking peptides and antibody fragments at later time points (e.g., 24h) for imaging. Within a theranostic framework, this imaging capability is used to non-invasively monitor the biodistribution and perform dosimetry for the highly effective, co-emitted beta-particle therapeutic dose.

Fig.1 Schematic representation of indirect radiolabeling of antibodies with generator eluted [¹⁸⁸Re]ReO₄⁻ using the prelabeling approach. (UCCELLI L, et al., 2017)

¹⁸⁸Re 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

The team of Alfa Cytology has mastered the unique radiochemistry of Rhenium-188, using the ¹⁸⁸W/¹⁸⁸Re generator to develop potent theranostic agents for high-energy beta-particle therapy and simultaneous SPECT imaging. Collaborate with Alfa Cytology to utilize this versatile isotope and convert your targeting molecules into image-guided therapy candidates.

Custom ¹⁸⁸Re Conjugation Service

The ¹⁸⁸Re conjugation service specializes in the synthesis of theranostic agents by attaching the generator-produced radionuclide, Rhenium-188, to targeting vectors with rapid to intermediate pharmacokinetics, such as peptides, small molecules, and engineered antibody fragments.

Small-Molecule Radionuclide Conjugate (SMRC)

Antibody-Radionuclide Conjugate (ARC)

Peptide-Radionuclide Conjugate (PRC)

siRNA-Radionuclide Conjugate

Workflow for Developing ¹⁸⁸Re-Radiolabeled Antibody Conjugates

¹⁸⁸Re Custom Antibody Labeling

• Strategy & Reagent Selection: Meticulous consideration is given to the planned use and the target molecule's structure. For best labeling efficiency and in vivo stability, the right choice of conjugation chemistry and bifunctional chelator is indispensable.
• Antibody Pretreatment & Conjugation: The chosen BFC is covalently bonded to the antibody and often attaches to amino acids like lysine or cysteine. Conditions of the reaction are carefully tuned to optimize stoichiometry while maintaining the structural and binding integrity of the antibody.
• Intermediate Purification: To ensure high purity and prevent interference during the next step of the process, which is radiolabeling, unreacted chelator and side products must be removed from the chelator-antibody conjugate by methods such as size-exclusion chromatography (SEC) or dialysis.
• Custom Radiosynthesis: The purified chelator-antibody conjugate is combined under tailored conditions with sodium perrhenate (¹⁸⁸ReO₄⁻). Temperature, pH, and incubation time are carefully adjusted and controlled to maximize the radiochemical yield and specific activity.

Purification & Quality Control

The incorporation of ¹⁸⁸Re is verified after labeling. The isotopic labeling, purity, and stability of the compound are evaluated with liquid chromatography (LC), mass spectrometry (MS), and scintillation counting, and must satisfy biomedical research standards.

In Vitro Evaluation

In vitro tests are performed to evaluate the biological properties of the ¹⁸⁸Re-labeled radiopharmaceutical. This includes studying its interaction with target receptors, cellular uptake, metabolic stability, and other pharmacological properties.

In Vivo Evaluation

At this crucial stage, quantitative investigation of biodistribution and pharmacokinetics (PK) consists of computing bioavailability and measuring the clearance of the agent from the body. Further, SPECT imaging is conducted in pertinent disease models to ascertain and confirm the agent's specific target engagement and ultimately validate the agent's diagnostic capability using in vivo blocking studies.

Applications of ¹⁸⁸Re-Radiolabeling

The applications of ¹⁸⁸Re-radiolabeling focus on developing image-guided radiotherapy on account of its convenient generator-based production and its powerful combination of beta-particle and quantitative SPECT imaging.

Image-Guided Radionuclide
Therapy Development

• Peptide Receptor Radionuclide Therapy (PRRT)
• Radioimmunotherapy (RIT) with Antibody Fragments and Peptides
• Small Molecule-Based Radioligand Therapy
• Development of Novel Theranostic Bioconjugates
• Targeting of Cell Surface Antigens (e.g., FAP, PSMA)
• Development of Radiolabeled Nanoparticles
• More

Adjuvant Therapeutic Strategies

• Palliative Therapy for Bone Metastases
• Radiosynovectomy for Inflammatory Joint Conditions
• Adjuvant Therapy to Surgery or External Beam Radiation
• Symptom Palliation in Metastatic Disease
• More

Using our extensive knowledge on the chemistry of rhenium and technetium, we are very good at developing strong, generator-based ¹⁸⁸Re-conjugates that offer powerful beta-particle therapy along with SPECT imaging. We invite you to contact us to understand how our specialized capabilities can help you create a powerful image-guided therapeutic pharmaceutical and speed up its therapeutic program.

Reference

1. UCCELLI L, MARTINI P, PASQUALI M, et al. Monoclonal Antibodies Radiolabeling with Rhenium-188 for Radioimmunotherapy [J]. BioMed Research International, 2017, 2017: 5923609.

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