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5-Aminoisophthalic acid and 5-nitroisophthalic acid (5-NIPA) are potential impurities in preparations of 5-amino-2,4,6-triiodoisophthalic acid, which is a key intermediate in the synthesis of the iodinated contrast agent iopamidol. We have studied their mutagenicity in silico (quantitative structure-activity relationships, QSAR) and by the bacterial reverse mutation assay (Ames test). First, the compounds were screened with the tools Derek Nexus™ and Leadscope®. Both compounds were flagged as potentially mutagenic (class 3 under ICH M7). However, contrary to the in silico prediction, neither chemical was mutagenic in the Ames test (plate incorporation method) with or without S9 metabolic activation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Optical imaging (OI) is gaining increasing attention in medicine as a non-invasive diagnostic imaging technology and as a useful tool for image-guided surgery. OI exploits the light emitted in the near-infrared region by fluorescent molecules able to penetrate living tissues. Cyanines are an important class of fluorescent molecules and by their conjugation to peptides it is possible to achieve optical imaging of tumours by selective targeting. We report here the improvements obtained in the synthesis of DA364, a small fluorescent probe (1.5 kDa) prepared by conjugation of pentamethine cyanine Cy5.5 to an RGD peptidomimetic, which can target tumour cells overexpressing integrin α v β 3 receptors.

PhotoAcoustic Imaging (PAI) is a biomedical imaging modality currently under evaluation in preclinical and clinical settings. In this work, ICG is coupled to an integrin binding vector (ICG-RGD) to combine the good photoacoustic properties of ICG and the favourable α v β 3 -binding capabilities of a small RGD cyclic peptidomimetic. ICG-RGD is characterized in terms of physicochemical properties, biodistribution and imaging performance. Tumor uptake was assessed in subcutaneous xenograft mouse models of human glioblastoma (U-87MG, high α v β 3 expression) and epidermoid carcinoma (A431, low α v β 3 expression). ICG and ICG-RGD showed high PA signal in tumors already after 15 min post-injection. At later time points the signal of ICG rapidly decreased, while ICG-RGD showed sustained uptake in U-87MG but not in A431 tumors, likely due to the integrin-mediated retention of the probe. In conclusion, ICG-RGD is a novel targeted contrast agents for PAI with superior biodistribution, tumor uptake properties and diagnostic value compared to ICG.

We report the synthesis of novel chelates of Gd and (68)Ga with DPTA, DOTA, HP-DOA3, as well as with AAZTA, a novel chelating agent developed by our research group. These chelating agents were appropriately conjugated, prior to metal complexation, with DB58, an RGD peptidomimetic, conformationally constrained on an azabicycloalkane scaffold and endowed with high affinity for integrin α(ν)β(3) . Because α(ν)β(3) is involved in neo-angiogenesis in solid tumors and is also directly expressed in cancer cells (e.g. glioblastomas, melanomas) and ovarian, breast, and prostate cancers, these constructs could prove useful as molecular imaging probes in cancer diagnosis by MRI or PET techniques. Molecular modeling, integrin binding assays, and relaxivity assessments allowed the selection of compounds suitable for multiple expression on dendrimeric or nanoparticulate structures. These results also led us to an exploratory investigation of (68)Ga complexation for the promising (68)Ga-PET technique; the AAZTA complex 15((68)Ga) exhibited uptake in a xenograft model of glioblastoma, suggesting potentially useful developments with new probes with improved affinity., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)