¹³¹I-Radiolabeling Service

¹³¹I-radiolabeling uses prosthetic-group strategies or electrophilic radioiodination incorporating the β/γ-emitting isotope into small molecules, peptides, or antibodies, for the targeted radiotherapy, SPECT imaging, and dosimetry. At Alfa Cytology, we offer high-quality ¹³¹I-radiolabeling services for preclinical studies. Moreover, we do site-selective chemistry and radiochemical QC (radiochemical purity, stability, and identity) for different vector types.

Introduction to ¹³¹I Isotopes

Iodine-131 (¹³¹I) is a radioisotope that is produced in a reactor and retains importance in nuclear medicine as a theranostic agent. It has a half-life of 8 days and a dual decay mode, which releases both cytotoxic beta-minus particles (β^-) for therapy and gamma photons for post-therapy SPECT imaging. Its potent beta radiation makes it highly effective for ablating tissue as the gold standard in the therapy of hyperthyroidism and thyroid cancer. Although its gamma energy is not ideal for high-resolution imaging, biodistribution and dosimetry after therapy can be sufficiently evaluated.

¹³¹I-Labeling for Radiopharmaceutical

Incorporation of iodine-131 into small molecules, peptides, and antibodies is a method that is highly essential for pinpoint targeted radiotherapy, molecular imaging, and dosimetry. The process utilizes electrophilic iodination or prosthetic-group labeling, ensuring minimal alteration to the biological activity. ¹³¹I-labeled compounds may be analyzed by SPECT imaging, which allows one to investigate their pharmacokinetics, distribution within the body, and tumor targeting at the preclinical stage.

Fig 1. The prediction of the radiosynthesis reaction of [¹³¹I] I-AM. (NURHIDAYAH W, et al., 2023)

¹³¹I 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.

Features of ¹³¹I-Radiopharmaceutical

Our Services

Utilizing advanced radiochemistry techniques tailored for maximum radiochemical purity and stability, Alfa Cytology offers highly precise ¹³¹I-labeling services. With labeling of a multitude of biomolecules, we can perform dependable in vivo tracking and quantitative imaging throughout preclinical analysis.

Custom ¹³¹I Conjugation Service

¹³¹I conjugation service offers tailored solutions for incorporating iodine-131 into biomolecules, ensuring precise radiolabeling for targeted therapy, molecular imaging, and dosimetry in preclinical research.

Small-Molecule Radionuclide Conjugate (SMRC)

Antibody-Radionuclide Conjugate (ARC)

Peptide-Radionuclide Conjugate (PRC)

siRNA-Radionuclide Conjugate

Workflow for Developing ¹³¹I-Radiolabeled Antibody Conjugates

¹³¹I Custom Antibody Labeling

Producing a quality ¹³¹I-radiolabeled antibody entails have various stages that require care and skill. Each step in our workflow is designed to achieve the highest efficiency in labeling and the highest retention of the antibody's biological function.

• Strategy & Reagent Selection: In this phase, defining the best labeling method is essential. Your needs in stability, immunoreactivity, and the application guide our specialists in selecting either direct or indirect labeling. We determine the key parameters such as specific activity, radionuclide purity, and formulation.
• Antibody Modification & Conjugation Prep: For indirect labeling, we first conjugate your antibody to a bifunctional chelator under optimized conditions. For direct labeling, the antibody is prepared in a desired reaction buffer. This not only maximizes the labeling but also preserves the antibody function.
• Custom Radiosynthesis: At the core of our service is the effective implementation of ¹³¹I incorporation using established techniques (e.g., Iodogen). Radiolabeling is carried out in a shielded environment by qualified radiochemists. To guarantee high radiochemical yield while preserving the functionality of the antibody, the reaction is meticulously controlled and monitored.

Purification & Quality Control

After labeling, the compound is verified for successful incorporation of ¹³¹I. Analytical methods, such as liquid chromatography (LC), mass spectrometry (MS), and scintillation counting, are used to confirm the correct isotopic labeling, purity, and stability of the compound, ensuring that it meets the necessary standards for biological studies.

In Vitro Evaluation

In vitro tests are performed to evaluate the biological properties of the ¹³¹I-labeled radiopharmaceutical. This includes studying its interaction with target receptors, cellular uptake, metabolic stability, and other pharmacological properties.

In Vivo Evaluation

This essential step begins with quantitative biodistribution and pharmacokinetic (PK) analyses to assess in detail uptake and clearance from different organs and the body as a whole. Later, SPECT imaging in pertinent pathology models serves to demonstrate and analyze the agent's in vivo target specificity and diagnostic capability through blocking experiments.

Applications of ¹³¹I-Radiolabeling

Applications of ¹³¹I-radiolabeling include targeted radiotherapy, SPECT imaging, and pharmacokinetic studies, enabling detailed tracking of radiolabeled compounds in preclinical models for therapeutic and diagnostic insights.

Alfa Cytology offers a comprehensive, one-stop development platform for various forms of ¹³¹I labeling, providing end-to-end solutions tailored to your research needs. If you encounter any challenges during the process, please contact us for expert assistance and support.

Reference

1. NURHIDAYAH W, WIDYASARI E M, DARUWATI I, et al. Radiosynthesis, Stability, Lipophilicity, and Cellular Uptake Evaluations of [(¹³¹)I]Iodine-α-Mangostin for Breast Cancer Diagnosis and Therapy [J]. International journal of molecular sciences, 2023, 24(10).

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