Preliminary Study of a 1,5-Benzodiazepine-Derivative Labelled with Indium-111 for CCK-2 Receptor Targeting

The cholecystokinin-2 receptor (CCK-2R) is overexpressed in several human cancers but displays limited expression in normal tissues. For this reason, it is a suitable target for developing specific radiotracers. In this study, a nastorazepide-based ligand functionalized with a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator (IP-001) was synthesized and labelled with indium-111. The radiolabeling process yielded >95% with a molar activity of 10 MBq/nmol and a radiochemical purity of >98%. Stability studies have shown a remarkable resistance to degradation (>93%) within 120 h of incubation in human blood. The in vitro uptake of [¹¹¹In]In-IP-001 was assessed for up to 24 h on a high CCK-2R-expressing tumor cell line (A549) showing maximal accumulation after 4 h of incubation. Biodistribution and single photon emission tomography (SPECT)/CT imaging were evaluated on BALB/c nude mice bearing A549 xenograft tumors. Implanted tumors could be clearly visualized after only 4 h post injection (2.36 ± 0.26% ID/cc), although a high amount of radiotracer was also found in the liver, kidneys, and spleen (8.25 ± 2.21%, 6.99 ± 0.97%, and 3.88 ± 0.36% ID/cc, respectively). Clearance was slow by both hepatobiliary and renal excretion. Tumor retention persisted for up to 24 h, with the tumor to organs ratio increasing over-time and ending with a tumor uptake (1.52 ± 0.71% ID/cc) comparable to liver and kidneys.     

A novel convenient synthesis of benzoquinazolines

[reaction: see text] A novel synthetic pathway to benzoquinazolines from naphthylamines is reported. Benzoquinazoline nucleus was cyclized in good yield from N-protected naphthylamines using hexamethylenetetramine in TFA and potassium ferricyanide in aqueous ethanolic KOH. This method is efficient and convenient with respect to previously reported synthetic pathways.     

The ISOLPHARM project: ISOL-based production of radionuclides for medical applications

Radionuclides for radiopharmaceuticals can be produced in cyclotrons or nuclear reactors. Each of these production modes has serious issues, such as high target costs, production of long-lived wastes and contaminants, expensive separation. For this reason, new methods are under consideration for the production of highly pure radionuclides. The ISOL (Isotope Separation On-Line) method is the major technique for the production of radioactive ion beams for nuclear physics applications. The SPES-ISOLPHARM project at INFN-LNL (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Legnaro) is a feasibility study for the production of medical isotopes exploiting the ISOL method. The ongoing activities concerning a recent experiment focused on ¹¹¹Ag, a study performed in collaboration with Padova and Trento Universities, is presented.

     

A microwave improvement in the synthesis of the quinazoline scaffold

A rapid and efficient microwave-assisted protocol is described that greatly improves a recent synthetic method developed for quinazoline synthesis. The synthetic protocol is based on the use of cycles of microwave irradiation. The optimization process is reported and the experimental results are compared with those of the conventional synthetic route.     

A new access to quinazolines from simple anilines

A new synthetic pathway to quinazolines is described. This new method uses hexamethylenetetramine in TFA and potassium ferricyanide in aqueous ethanolic KOH, starting from simple N-protected anilines. The method affords substituted quinazolines with high selectivities and good yields, reducing reaction-time and work-up operations.     

Autogrid-based clustering of kinases: selection of representative conformations for docking purposes

The selection of the most appropriate protein conformation is a crucial aspect in molecular docking experiments. In order to reduce the errors arising from the use of a single protein conformation, several authors suggest the use of several tridimensional structures for the target. However, the selection of the most appropriate protein conformations still remains a challenging goal. The protein 3D-structures selection is mainly performed based on pairwise root-mean-square-deviation (RMSD) values computation, followed by hierarchical clustering. Herein we report an alternative strategy, based on the computation of only two atom affinity map for each protein conformation, followed by multivariate analysis and hierarchical clustering. This methodology was applied on seven different kinases of pharmaceutical interest. The comparison with the classical RMSD-based strategy was based on cross-docking of co-crystallized ligands. In the case of epidermal growth factor receptor kinase, also the docking performance on 220 known ligands were evaluated, followed by 3D-QSAR studies. In all the cases, the herein proposed methodology outperformed the RMSD-based one.     

UHPLC-DAD method for the determination of neonicotinoid insecticides in single bees and its relevance in honeybee colony loss investigations

In the understanding of colony loss phenomena, a worldwide crisis of honeybee colonies which has serious consequences for both apiculture and bee-pollination-dependent farm production, analytical chemistry can play an important role. For instance, rapid and accurate analytical procedures are currently required to better assess the effects of neonicotinoid insecticides on honeybee health. Since their introduction in agriculture, neonicotinoid insecticides have been blamed for being highly toxic to honeybees, possibly at the nanogram per bee level or lower. As a consequence, most of the analytical methods recently optimized have focused on the analysis of ultratraces of neonicotinoids using liquid chromatography–mass spectrometry techniques to study the effects of sublethal doses. However, recent evidences on two novel routes—seedling guttations and seed coating particulate, both associated with corn crops—that may expose honeybees to huge amounts of neonicotinoids in the field, with instantly lethal effects, suggest that selected procedures need optimizing. In the present work, a simplified ultra-high-performance liquid chromatography–diode-array detection method for the determination of neonicotinoids in single bees has been optimized and validated. The method ensures good selectivity, good accuracy, and adequate detection limits, which make it suitable for the purpose, while maintaining its ability to evaluate exposure variability of individual bees. It has been successfully applied to the analysis of bees in free flight over an experimental sowing field, with the bees therefore being exposed to seed coating particulate released by the pneumatic drilling machine.     

A novel approach to quinazolin-4(3H)-one via quinazoline oxidation: an improved synthesis of 4-anilinoquinazolines

A novel strategy to prepare 4-anilinoquinazoline derivatives based on the oxidation of the quinazoline ring is described. Quinazoline oxidation has been investigated and improved, thus leading to an efficient and high yielding method to quinazolin-4(3H)-ones. Efficiency of this approach has been evaluated synthesizing four well known tyrosine kinase inhibitors and comparing the obtained yields with those achievable through conventional synthetic methods.