2-S-(4-Isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid

Name: 2-S-(4-Isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid
SKU: ACM147597668
Rating: 5 (1 reviews)

CAS

147597-66-8

Catalog Number

ACM147597668

Category

Main Products

Molecular Weight

559.9

Molecular Formula

C20H26N4O6S·3HCl

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Specification

Synonyms

p-SCN-Bn-NOTA

Appearance

Solid

Synthesis of p-SCN-Bn-NOTA Modified Somatropins

Bracke, Nathalie, et al. Journal of Pharmaceutical and Biomedical Analysis, 2014, 96, 1-9.

This study described the synthesis of somatropins modified at the ε-amino group of lysine with the acylated chelator S-2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA). p-SCN-Bn-NOTA is a well-established hexadentate BFCA that forms extremely stable complexes with Ga(III). This synthetic procedure can be used to produce target-specific radiopharmaceuticals for further investigations into treatment and visualization of somatropin-specific cancers.
Synthetic procedure of Ga labeled NOTA-somatropin
· One milligram of somatropin (=45 nmol) was dissolved in 200 µL of carbonate buffer (pH 9.0; 0.1 M) and mixed with varying volumes of 20 mM p-SCN-Bn-NOTA in the same buffer, then diluted to 350 µL. This process resulted in molar ratios of 1:1, 3:1, and 10:1 of NOTA to somatropin. The resulting mixtures were incubated for 20 hours at 20 °C in the dark, with shaking at 300 rpm. The protein fraction was then collected by loading the sample onto a PD-10 Sephadex G-25 M column that had been equilibrated with a digestion buffer consisting of 10 mM ACES and 20 mM CaCl2 at pH 7.0. Following this, the samples were freeze-dried for subsequent analytical characterization.
· To label 3:1 NOTA-somatropin with gallium, a 45 nmol lyophilized protein sample was reconstituted in 450 µL of 0.6 mM GaCl3 and 0.1 M HCl, providing a 2:1 molar excess relative to the original p-SCN-Bn-NOTA concentration. Next, 20 µL of 2 M NaOH and 40 µL of a 0.1 M ammonium acetate buffer containing 0.2 mM acetylacetone (pH 5.5) were added. The mixture was then thoroughly combined and incubated for 1 hour at 20 °C in the dark while shaking at 300 rpm.

Comparison of NOTA and PCTA Chelates in 68Ga Radiolabeled Small Peptide Imaging

Ferreira, Cara L., et al. Bioconjugate Chemistry, 2012, 23(11), 2239-2246.

This work compared the chelates p-SCN-Bn-PCTA and p-SCN-Bn-NOTA in combination with cyclo-RGDyK for 68Ga radiolabeling and small peptide imaging. The following are the similarities and differences between the two:
· Both pSCN-Bn-PCTA and p-SCN-Bn-NOTA were conjugated to cyclo-RGDyK to target the αvβ3 integrin. The resulting conjugates, PCTA-RGD and NOTA-RGD, facilitated efficient room temperature radiolabeling, producing 68Ga-radiolabeled products with high radiochemical yields (RCY) and effective specific activity. The radiolabeling process is suitable for straightforward kit-type radiopharmaceutical preparation, making it ideal for application in a radiopharmacy environment.
· While 68Ga-PCTA-RGD showed reduced stability after 4 hours in the presence of apo-transferrin compared to 68Ga-NOTA-RGD, no differences in stability were noted during the 2-hour optimal window for imaging.
· Aside from kidney uptake, the in vivo uptake and clearance of 68Ga-radiolabeled PCTA-RGD and NOTA-RGD were statistically similar; both exhibited specific uptake in tumors and cleared rapidly from background tissues such as blood and muscle.
· However, 68Ga-radiolabeled PCTA-RGD had slightly lower average kidney uptake, resulting in a better tumor-to-kidney ratio compared to 68Ga-radiolabeled NOTA-RGD, which may enhance its utility for imaging applications near the kidneys.