¹⁰³Pd-Radiolabeling Service

The ¹⁰³Pd-radiolabeling service is aimed at designing new types of radiotherapeutics by equipping Auger electron emitters, Palladium-103, to targeting molecules for destructive, subcellular cancer therapy. At Alfa Cytology, the capability of the radiometal chemists to tailor radiolabeled compounds ensures that your ¹⁰³Pd-labeled candidates are synthesized to a high standard and delivered as well-characterized compounds poised to advance your therapeutic programs.

Introduction to ¹⁰³Pd Isotopes

As a low-energy radioisotope with a half-life of 16.99 days, Palladium-103 (¹⁰³Pd) decays through electron capture. Characteristics of this decay process are the emission of X-rays of approximately 21 keV and a cascade of highly cytotoxic Auger electrons. Although ¹⁰³Pd has been used for over a decade in low-dose rate brachytherapy seeds for prostate cancer, the unique emission of the electrons makes it a highly attractive candidate in the development of targeted radiopharmaceuticals.

¹⁰³Pd-Labeling for SPECT Imaging

¹⁰³Pd labeling is a new approach to developing radiopharmaceuticals with highly localized and potent cellular cytotoxicity. ¹⁰³Pd has a 17-day half-life and decays solely by electron capture, releasing a dense shower of low-energy Auger electrons. These electrons deposit energy within a very short range (within several nanometers), producing highly intricate damage to the DNA and resulting in strong cell-killing capabilities. These qualities make ¹⁰³Pd-labeled agents very attractive for use in therapies seeking targeted destruction of micrometastases or disseminated tumor cells with minimal damage to surrounding tissues.

Fig.1 Synthesis of SSIB-[16]aneS4 (5) and chelation of [¹⁰³Pd]Pd to form [¹⁰³Pd]Pd-SSIB-[16]AneS4 (6) (SPORER E, et al., 2024)

Advantages of ¹⁰³Pd -Labeling

Delivering its therapeutic payloads on a subcellular level allows ¹⁰³Pd-labeling to gain a unique set of benefits unmatched by conventional beta or alpha-emitting radionuclides.

Our Services

Here at Alfa Cytology, we focus on custom conjugation of targeting molecules with ¹⁰³Pd, applying extensive purification and advanced analytics to guarantee exceptional product integrity and performance. Our experienced radiochemists tackle the complex aspects of ¹⁰³Pd chemistry to deliver reliable, well-characterized agents to bolster your preclinical research initiatives.

Custom ¹⁰³Pd Conjugation Service

From monoclonal antibodies and peptides to small-molecule inhibitors, our service custom-conjugates ¹⁰³Pd to your specific targeting molecule to engineer potent, next-generation Auger electron therapies.

Small-Molecule Radionuclide Conjugate (SMRC)

Antibody-Radionuclide Conjugate (ARC)

Peptide-Radionuclide Conjugate (PRC)

siRNA-Radionuclide Conjugate

Workflow for Developing ¹⁰³Pd-Radiolabeled Small Molecule Conjugates

¹⁰³Pd Custom Small Molecule Labeling

• Strategy & Reagent Selection: Starting with a thorough examination of the target molecule's structure and functional groups for the most effective labeling approach. Selecting or custom-synthesizing the required ¹⁰³Pd precursor and bifunctional chelator for the purpose of effective and stable radiometal incorporation.
• Protocol Optimization: Optimization of the labeling protocol involves tailoring key variables, including the molar ratios of the reactants, pH, temperature, time of reaction, and so forth.
• Custom Radiosynthesis: Carrying out the radiosynthesis to ensure the complexation of ¹⁰³Pd with the small molecule target under tightly controlled conditions. Utilizing real-time monitoring to assess the reaction and optimize for the highest specific activity and yield.

Purification & Quality Control

Following labeling, verification is performed on the compound to assess successful incorporation of ¹⁰³Pd. For this purpose, correct isotopic labeling, purity, and compound stability to biological studies standards are confirmed by liquid chromatography and mass spectrometry, followed by scintillation counting.

In Vitro Evaluation

In vitro tests are performed to evaluate the biological properties of the ¹⁰³Pd-labeled radiopharmaceutical. This includes studying its interaction with target receptors, cellular uptake, metabolic stability, and other pharmacological properties.

In Vivo Evaluation

To start, this critical phase considers the quantitative biodistribution and pharmacokinetic studies, which aim to confirm the distribution and clearance rates of an agent in an organ and the entire body, respectively. Afterwards, in relevant disease models, SPECT imaging is utilized to verify the engagement of specific targets and, through in vivo blocking studies, to ascertain the agent's diagnostic capacity.

Applications of ¹⁰³Pd-Radiolabeling

Leveraging its unique, short-range Auger electron emissions, ¹⁰³Pd-radiolabeling enables highly precise therapeutic and research applications at the cellular and subcellular level.

Alfa Cytology provides specialized scientific support and rigorous synthesis capabilities to support the entire workflow of ¹⁰³Pd conjugated, for the development of Auger electron therapy for radiopharmaceutical targeting. We are eager and ready to collaborate. Do not hesitate to reach out to us to discuss the specific needs for your project and our services.

Reference

1. SPORER E, DEVILLE C, STRAATHOF N J W, et al. Optimized chelator and nanoparticle strategies for high-activity (¹⁰³)Pd-loaded biodegradable brachytherapy seeds [J]. EJNMMI radiopharmacy and chemistry, 2024, 9(1): 92.

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