DOTA-GA(tBu)₄ (DOTAGA-tetra(tert-butyl ester))

DOTA-GA(tBu)₄ is the tetra-tert-butyl ester protected form of DOTAGA (1,4,7,10-tetraazacyclododecane-1-glutaric acid-4,7,10-triacetic acid), a bifunctional macrocyclic chelator derived from DOTA. It features four tert-butyl protecting groups on the carboxylic acid arms, providing excellent stability during synthesis and conjugation steps. The remaining free carboxylic acid on the glutaric side chain enables straightforward amide coupling to biomolecules (e.g., peptides, antibodies) prior to deprotection and metal complexation. This protected precursor is widely employed in the development of targeted radiopharmaceuticals for PET/SPECT imaging and radionuclide therapy.

Key Features and Benefits:

• Protected Carboxyl Groups: Tert-butyl esters ensure stability under basic/neutral conditions and are readily removed by mild acid (e.g., TFA/DCM).
• Bifunctional Design: Allows site-specific conjugation while preserving strong, kinetically inert metal chelation.
• Improved Properties over DOTA: The additional carboxyl group in DOTAGA leads to more hydrophilic complexes with better pharmacokinetics (e.g., reduced liver uptake).
• High Chelating Affinity: Forms stable complexes with diagnostic (⁶⁸Ga, ⁶⁴Cu, ¹¹¹In) and therapeutic (¹⁷⁷Lu, ²²⁵Ac, ⁹⁰Y) radionuclides.
• Research & Clinical Relevance: Commonly used for labeling somatostatin analogs (e.g., TATE), PSMA ligands, and other targeting vectors.

Physical and Chemical Properties:

• Appearance: White to off-white solid powder
• Purity (HPLC): ≥ 95–98% (typically ≥96–98.7% from commercial suppliers)
• Solubility: Soluble in organic solvents (DCM, DMF, DMSO, acetonitrile); poorly soluble in water
• Boiling Point (predicted): ≈710 ±60 °C
• Density (predicted): ≈1.081 ±0.06 g/cm³

Storage and Handling:

• Recommended Storage: -20°C (powder form) in a tightly sealed container, protected from moisture and light
• Solution Storage: For prepared solutions, aliquot and store at -80°C for up to 6 months or -20°C for up to 1 month to avoid freeze-thaw degradation
• Shelf Life: Stable for several years when stored properly
• Handling: Research use only; use appropriate PPE; avoid inhalation, skin/eye contact

Applications:

• Precursor for peptide conjugation and subsequent radiolabeling (e.g., ⁶⁸Ga-DOTAGA-TATE for neuroendocrine tumor PET imaging)
• Synthesis of targeted radiotracers for oncology, theranostics, and molecular imaging
• Development of bifunctional chelators for bioconjugation to peptides, proteins, or nanoparticles
• Research in radiometal chemistry, MRI contrast agents (e.g., Gd-DOTAGA derivatives), and targeted radionuclide therapy

This high-purity protected chelator is a critical building block for advanced radiopharmaceutical research and development. For bulk quantities, custom synthesis, or detailed certificates of analysis (CoA), please contact our sales team.