Retention Data for Some Carbonyl Derivatives of Imidazo[2,1-c][1,2,4]triazine in Reversed-Phase Systems in TLC and HPLC and their Use for Determination of Lipophilicity. Part 1. Lipophilicity of 8-Aryl-3-phenyl-6,7-dihydro-4H-imidazo[2,1-c][1,2,4]triazin-4-ones

JPC – Journal of Planar Chromatography – Modern TLC - Thirteen carbonyl derivatives of imidazo [2,1-c][1,2,4]triazine have been synthesized as a new bioactive set of substances....     

Square-wave adsorptive stripping voltammetric approaches at two in situ modified electrodes as first analytical methods for the quantitative determination of a new anticancer drug candidate

The two adsorptive stripping voltammetric approaches for detection and quantitative determination of diethyl (2E)-2-{(2E)-[1-(4-methylphenyl)imidazolidin-2-ylidene]hydrazinylidene}butanedioate (DIB)—a novel molecule of medical importance—using two sensitive sensors based on modified glassy carbon electrodes as reusable sensors, were developed for the first time. The proposed electrochemical methods are based on adsorptive/reductive behaviour of DIB at two modified carbonic electrodes: a bismuth film-modified glassy carbon electrode (BiF/GCE) and a lead film-modified glassy carbon electrode (PbF/GCE). The electron gain mechanism for the electrochemical reduction of DIB on both developed sensors was proposed for the first time. To achieve the highest sensitivity in adsorptive stripping determinations, various experimental variables (e.g. the composition and pH of the supporting electrolytes, deposition conditions of bismuth and lead films, concentrations of plating solutions, accumulation times and potentials of DIB, etc.) were extensively examined. The comparison of validation parameters obtained during the determination of DIB at two sensors was presented. The excellent linear correlation was found between the monitored adsorptive stripping voltammetric peak current and the DIB concentration in the range of 15–600 μg L⁻¹ at an accumulation time of 30 s (with LOD = 4.2 μg L⁻¹ and LOQ = 14.0 μg L⁻¹) using the BiF/GCE as a sensor. Furthermore, the excellent linear relationship was confirmed between the monitored adsorptive stripping voltammetric peak current and the DIB concentration in the range of 9–900 μg L⁻¹ at an accumulation time of 10 s (with better LOD = 1.5 μg L⁻¹ and LOQ = 5.0 μg L⁻¹), employing the PbF/GCE as a sensor. The two optimized adsorptive stripping voltammetric approaches—as facile, sensitive, reliable and inexpensive—were successfully used as first methods for the quantitative analysis of a novel anticancer agent (DIB) in its pure pharmaceutically acceptable form. However, the practical applicability of square-wave adsorptive stripping voltammetric determination of the electroactive DIB molecule at a PbF/GCE, as the modified electrode of higher sensitivity, was presented after its successful solid phase extraction from a real serum sample.

     

Electron ionization mass spectra of 8‐aryl‐3,4‐dioxo‐2H,8H‐6,7‐dihydroimidazo[2,1‐c][1,2,4]triazines. Do they exhibit tautomerism in the gas phase?

The electron ionization mass spectra of the title compounds (1: a R = H, b 2-CH(3), c 4-CH(3), d 2,3-diMe, e 2-OCH(3), f 4-OCH(3), g 2-Cl, h 3-Cl, i 4-Cl, j 3,4-diCl) were recorded at 70 eV to determine the effects of substituents and the possible keto-enol tautomerism. The compounds showed several common fragment ions but also fragment ions which divided them into three classes, namely 1a-1d (parent compound and Me-substituted derivatives), 1e and 1f (MeO-substituted derivatives), and 1g-1j (Cl-substituted derivatives). The presence of the HOCN(+.) ion as well as the exponential dependence of its total ion current in the case of p- and also 3-Cl-substituted compounds (1a, c, f, h-j) on the Hammett sigma constants and the loss of CHO or one or two HOCN moieties can be somewhat easier explained by the presence of the enol form but as a whole the results support the predominance of the keto form, in parallel to the situation in solution.     

Determination of the Lipophilicity of Twenty-Seven Imidazo[2,1-c][1,2,4]triazine Derivatives with Strong Biological Activity by Reversed-Phase TLC. Comparison with Results Obtained by Use of Computational Algorithms

JPC – Journal of Planar Chromatography – Modern TLC - The lipophilicity, log P, of 27 novel imidazo[2,1-c][1,2,4]triazine derivatives with strong biological activity has been determined...     

Thermal behaviour of antiproliferative active 3-(2-furanyl)-8-aryl-7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-ones

Journal of Thermal Analysis and Calorimetry - Thermal analysis is commonly used in the pharmaceutical field because it is an important tool in the solution of problems involving development,...     

Voltammetry as the First Method for Direct Determination of a Novel Antagonist of A2A Adenosine Receptors

In this article, for the first time, the analytical method for determination of a novel antagonist of A_2A adenosine receptors (8‐(4‐methoxyphenyl)‐4‐oxo‐4,6,7,8‐tetrahydroimidazo[2,1‐c][1,2,4]triazine‐3‐carbohydrazide, namely IMT), which can be used as a drug for liver diseases, was presented. For this purpose a commercially available boron‐doped diamond electrode (BDDE) in combination with differential pulse voltammetry (DPV) was applied. It was found by cyclic voltammetry (CV) that IMT displays at BDDE, as a sensor, two well‐defined oxidation peaks at potentials of 0.81 and 1.18 V and one reduction peak at 1.1 V vs. Ag/AgCl in 0.1 mol L^?1 acetate buffer (pH 4.5±0.1). The oxidation and reduction mechanism of IMT was proposed. The developed DPV method allowed the successful determination of IMT in the range of 0.05–50 μmol L^?1 with detection limit equal to 0.0094 μmol L^?1 and without any chemical modifications and electrochemical pretreatment of the electrode surface. The proposed procedure allows the determination of IMT in vitro directly from urine samples.     

Anti-Tumor Active Isopropylated Fused Azaisocytosine-Containing Congeners Are Safe for Developing Danio rerio as Well as Red Blood Cells and Activate Apoptotic Caspases in Human Breast Carcinoma Cells

New isopropylated fused azaisocytosine-containing congeners (I–VI) have previously been reported as promising anticancer drug candidates, so further research on these molecules in the preclinical development phase is fully justified and necessary. For this reason, in the present paper, we assess the toxicity/safety profiles of all the compounds using Danio rerio and red blood cell models, and examine the effect of the most selective congeners on the activation of apoptotic caspases in cancer and normal cells. In order to evaluate the effect of each molecule on the development of zebrafish embryos/larvae and to select the safest compounds for further study, various phenotypic parameters (i.e., mortality, hatchability, heart rate, heart oedema, yolk sac utilization, swim bladder development and body shape) were observed, and the half maximal lethal concentration, the maximal non-lethal concentration and no observed adverse effect concentration for each compound were established. The effect of all the isopropylated molecules was compared to that of an anticancer agent pemetrexed. The lipophilicity-dependent structure–toxicity correlations were also determined. To establish the possible interaction of the compounds with red blood cells, an ex vivo hemolysis test was performed. It was shown that almost all of the investigated isopropylated congeners have no adverse phenotypic effect on zebrafish development during five-day exposure at concentrations up to 50 μM (I–III) or up to 20 μM (IV–V), and that they are less toxic for embryos/larvae than pemetrexed, demonstrating their safety. At the same time, all the molecules did not adversely affect the red blood cells, which confirms their very good hemocompatibility. Moreover, they proved to be activators of apoptotic caspases, as they increased caspase-3, -7 and -9 levels in human breast carcinoma cells. The conducted research allows us to select—from among the anticancer active drug candidates—compounds that are safe for developing zebrafish and red blood cells, suitable for further in vivo pharmacological tests.