Radioiodinated Portable Albumin Binder as a Versatile Agent for in Vivo Imaging with Single-Photon Emission Computed Tomography

Abstract

In this study, radioiodinated 4-(p-iodophenyl)butyric acid ([ 131 I]IBA) was synthesized and evaluated as a portable albumin-binder for potential applications in single photon emission computed tomography imaging of blood pool, tumor, and lymph node with significantly improved pharmacokinetic properties. The [ 131 I]IBA was prepared under the catalyst of Cu 2 O/1,10-phenanthroline. After that, the albuminbinding capability of [ 131 I]IBA was tested in vitro, ex vivo, and in vivo, respectively. [ 131 I]IBA was obtained with very high radiolabeling yield (>99%) and good radiochemical purity (>98%) within 10 min. It binds to albumin effectively with high affinity (IC 50 = 46.5 μM) and has good stability. The results of biodistribution indicated that the [ 131 I]IBA was mainly accumulated in blood with good retention (10.51 ± 2.58% ID/g at 30 min p.i. and 4.63 ± 0.17%ID/g at 4 h p.i.). In the SPECT imaging of mice models with [ 131 I]IBA, blood pool, lymph node, and tumors could be imaged clearly with high target-to-background ratio. Overall, the radioiodinated albumin binder of [ 131 I]IBA with long blood half-life and excellent stability could be used to decorate diversified albumin-binding radioligands and developed as a versatile theranostic agent.

Radioiodinated 4-(p-Iodophenyl) Butanoic Acid-Modified Estradiol Derivative for ER Targeting SPECT Imaging

“…[ 131 I]IB-EE was almost completely cleared from the body except for the thyroid at 24 h p.i. We noticed that the extremely high thyroid uptake was different from the previously reported compounds ([ 131 I]IBA and [ 131 I]IA), 23 which were radioiodinated with the same method. Although the exact reason is not clear, it may be caused by different animal species.…”

“…The popularity and availability of SPECT give this 131 I-labeled agent a large advantage over the 18 F-labeled PET tracers. Most importantly, the copper-mediated radioiodination approach is also applicable to the other radioisotopes of iodine, such as 123 I and 124 I, which afford such an agent with a variety of functionalities for therapy or diagnosis with SPECT or PET imaging of ER-positive tumors …”

“…In this study, a radioiodinated albumin binder, 4-( p -iodophenyl) butyric acid (IPBA), − was introduced into ethinylestradiol to obtain a novel ER-targeted probe [ 131 I]­IPBA-EE (Figure ), which was expected to use IPBA to combine with albumin in plasma to protect estrogen derivatives from enzymatic degradation in the liver. , The synthesis, radiolabeling, metabolic stability, and targeting ability of [ 131 I]­IPBA-EE were characterized, and its feasibility for ER-positive breast cancer imaging was verified in tumor-bearing mice as well. To reduce the nonspecific uptake in the liver, a short polyethylene glycol (PEG3) was introduced to decrease the lipophilicity of the steroid molecule.…”

Tumor Noninvasive and Target Embolization Therapy Platform by Intravenous Injection Based on Acidic Microenvironment-Responsive Hyperbranched Poly(amino acid)s

“…Compared to fluorescence imaging in vivo, SPECT can analyze quantitatively and has a deep penetration capability. The nuclides commonly used in SPECT are mainly 131 I, 18 F, 99m Tc, and 111 In. − 131 I can not only be used to image tumor sites but also have therapeutic effects on tumor sites . It also has a longer half-life ( t 1/2 = 8.01 days), which can overcome the shortcomings of radionuclides such as 18F whose half-life in the human body is too short.…”

Med Chem Remote: The Frontiers in Medicinal Chemistry 2021

“…The first awardee, Nina Schützenmeister (University of Vienna), presented novel and efficient synthetic methods, which allowed access to natural product‐like analogues with antibacterial and antiviral activity. In her talk, she focused on the synthesis of marine natural products rubrolides and diorcinols and on synthetic analogues of Scleropentaside A [26,27] . As the second innovation prize awardee, Pierre Koch (University of Regensburg) presented studies aimed at selective kinase inhibitors that are able to cross the blood‐brain barrier.…”