Browsing by Author "Amudi, Karina"

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Electrochemical Determination of Cefotaxime, a Cephalosporin Group Drug, at a Boron-Doped Diamond Electrode
(Marmara Univ, 2022) Tunc, Bilal; Amudi, Karina; Pinar, PInar Talay
In this study, electrochemical analysis of cefotaxime, one of the third-generation cephalosporins, the semisynthetic antibiotic group of the b-Lactam family, with an anodic pre-treated boron-doped diamond electrode (APTBDDE) were investigated in a wide pH range. The cyclic voltametric (CV) and square-wave voltametric (SWV) techniques were applied for the rapid, sensitive, cheap, simple, and precise detection of CEF. The compound yielded two well-defined oxidation steps (Ia=1.1; IIa=1.5 V) in acidic, neutral, and alkaline media by employing SWV. Experimental conditions, namely pH, modulation amplitude, step potential, frequency, interference, and effect of scan rate were optimized. By employing SWV, there was a linear dependence of the oxidation peak current at +1.1 V and CEF concentration in the range of 1.0-20.0 mu g mL-1 (2.1x10-6 - 4.2x10-5 mol L-1), with a detection limit of 0.22 mu g mL-1 (4.6x10-7 mol L-1) in 0.1 mol L-1 phosphate buffer solution (pH 2.5). The practical applicability of the proposed method was tested with the quantification of CEF in the drug formulation.
Highly Selective Electrochemical Sensor for New Generation Targeted-Anticancer Drug Ibrutinib Using Newly Synthesized Nanomaterial Go-Nh Modified Glassy Carbon Electrode
(Elsevier Sci Ltd, 2023) Amudi, Karina; Yigit, Aybek; Menges, Nurettin; Pinar, Pinar Talay
Ibrutinib (IBR) is a small molecule new generation smart anti-cancer drug that is Bruton's tyrosine kinase (BTK) inhibitor. In this study, the sensitive and selective electrochemical sensor based on a modification of a glassy carbon electrode with a new GO-NH-B(OH)2 (graphene oxide boramidic acid) nanoparticles and Ag nano -particles (AgNPs) is proposed for IBR determination. GO-NH-B(OH)2@AgNPs/GCE was characterized by scan-ning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The performance of the electrode was evaluated with the parameters of electrode surface area (A), heterogeneous rate constant (ket), standard exchange current density (I0). The electrochemical determination of IBR in 0.1 M HNO3 solution was investigated at the surface of GO-NH-B(OH)2@AgNPs/GCE. Under optimized square wave voltammetric (SWV) conditions, peaks current at GO-NH-B(OH)2@AgNPs/GCE showed good linearity with the concentration of IBR in the operating range of 0.025-1.00 mu g mL-1 (5.7 x 10-8 - 2.3 x 10-6 M) with a detection limit (LOD) of 0.006 mu g mL-1 (1.36 x 10-8 M). Besides its high stability and reproducibility, the response of IBR at GO-NH-B (OH)2@AgNPs/GCE was not influenced by the presence of dopamine, uric acid, and ascorbic acid. The sensor has successfully caught IBR in pharmaceutical and human urine samples.
A New Synthetic Approach for Pyrazolo[1,5-A]pyrazine Derivatives and Their Antiproliferative Effects on Lung Adenocarcinoma Cell Line
(Springer, 2022) Uygun, Meltem Tan; Amudi, Karina; Turacli, Irem Dogan; Menges, Nurettin
Starting from the 3,5-dimethyl pyrazole ring and acetophenone derivatives, five different N-propargylated C-3 substituted pyrazoles were obtained. These derivatives were reacted with different amine derivatives using Cs2CO3 in methanol and 11 different pyrazolo [1,5-a] pyrazine-4(5H)-one derivatives were obtained, which are not found in the literature. The cytotoxic effects of these derivatives in the A549 cell line were investigated. The 160 mu M concentration of two derivatives was found to increase cell death rate to 50%, and two derivatives increased cell death rate by up to 40%. The structure-activity relationship (SAR) study revealed an amide group with a long alkyl chain and benzene ring with a p-CF3 group could be important for efficiency. With theoretical ADMET studies of pyrazolopyrazine derivatives, pharmacokinetic phases were predicted to be suitable.
Selective Rna Binding and Imaging With Imidazopyrazine-Based Fluorescent Molecule
(Pergamon–Elsevier Science Ltd, 2025) Sevincli, Zekiye Seyma; Amudi, Karina; Oncel, Buse Ceyda; Yurtcu, Erkan; Iseri, Ozlem Darcansoy; Menges, Nurettin
We report the synthesis and characterization of novel imidazopyrazine-based fluorescent molecules 5a and 5b targeting RNA and DNA binding. Molecule 5b showed superior photophysical properties with stable fluorescence and high quantum yield in various solvents. UV-Vis and fluorescence spectroscopy revealed strong RNA binding with time-dependent fluorescence quenching and increasing absorbance, suggesting groove binding or it-it stacking interactions. Furthermore, agarose gel electrophoresis further confirmed selective RNA binding of 5b. Imaging studies demonstrated that 5b penetrated into viable MCF-7 cells and selectively stained RNA and retained fluorescence for up to 8 h under ambient conditions. These findings advance the study of RNA dynamics in living cells, highlighting the potential of 5b for RNA-specific bioimaging and sensing applications.
Synthesis of Pyrrolizinone and Pyrrolizino[1,2-A]pyrrolizin Skeletons Starting From Pyrrole Through a Single-Step and Catalyst-Free Approach
(Georg Thieme verlag Kg, 2023) Amudi, Karina; Kuzu, Burak; Kolak, Seda; Genc, Hasan; Menges, Nurettin
1H-Pyrrole reacted with lactone-type 2,3-furandione derivatives in anhydrous diethyl ether at room temperature to give a series of derivatives of pyrrolizinone (which is among the most important al-kaloid skeletons) in a single step without a catalyst. Pyrrolizinone derivatives with a variety of substituents, such as phenyl, substituted phenyl, thienyl, trifluoromethyl, naphthyl, biphenylyl, ester, or oxalate, were obtained. The reaction of an equimolar amount of pyrrole gave pyrroliz-inones, whereas an excess of pyrrole gave pyrrolizino[1,2-a]pyrrolizin-5-ones containing a skeleton that had not previously been reported. The purified molecules were obtained in yields of up to 91%. One cyclization process was carried out on a gram scale, yielding 0.952 g (71%) of the corresponding product.