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    A Fluorometric Method for Diclofenac Determination in Liquid Formulations: Experimental and Computational Assessments
    (Wiley-V C H Verlag Gmbh, 2025) Sarkaya, Koray; Fitoz, Alper; Ergun, Ece; Orhan, Ersin; Ergun, Umit
    Diclofenac (DCF) is an important non-steroidal anti-inflammatory drug frequently used to relieve rheumatic pain and acute injuries. Therefore, determination of DCF in real-life samples using an efficient and cost-effective indirect method is vital in pharmaceutical science. The proposed novel method is based on the formation of a solid Zn-BMHM complex (chemosensor BMHM; (E)-1-((((1H-benzo[d]imidazol-2-yl)methyl)imino)methyl)-5-methylphenol) via the displacement of zinc ions from the Zn-DCF complex in an ethanol medium. The method consists of rapid precipitation steps that prevent interference effects and a turn-on fluorescence effect by using a chemosensor. The increase in fluorescence intensity was linearly correlated with the concentration of Zn-DCF solution over the range of 5.0-50.0 mu M (R2: 0.999) with a LOD value of 1.64 mu M. The method was applied to liquid pharmaceutical formulations and obtained excellent recovery values (99.09%-103.9%). Geometry optimization, molecular orbitals, and NBO population analyses were performed using density functional theory to display the exchange reaction's characteristics between ligand DCF and chemosensor BMHM. Global reactivity parameters and local interaction sites on the DCF and BMHM were examined in detail in view of the analyzed reaction. Theoretical assessments supported the analysis of reaction selectivity towards the BMHM ligand.
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    A Novel Benzimidazole-Based Chemosensor for Fluorometric Determination of Zinc Ions
    (Springer/Plenum Publishers, 2021) Orhan, Ersin; Ergun, Ece; Sarkaya, Koray; Ergun, Umit
    A simple and novel Schiff base chemosensor (BMHM) based on benzimidazole was synthesized. In ethanol-water (1:1, v/v) medium on varying concentrations of Zn2+ chemosensor exhibited a strong and quick turn on fluorescence response. The Zn2+ recognition was based on the Chelation-enhanced fluorescence effect. The binding constant and limit of detection for BMHM-Zn2+ complexation were estimated to be 7.99 x 104 M-1 and 0.148 mu M, respectively. The extreme fluorescent enhancement caused by Zn2+ binding in chemosensor BMHM occurred at a pH range of 6-7. The practical use of chemosensor BMHM was tested by determination of Zn2+ in real water samples and comparing the results with the data obtained using high resolution inductively coupled plasma mass spectrometry.
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    A potential new approach for preserving historical artifacts through gamma irradiation and green antimicrobials: Microbiological and theoretical screening
    (Pergamon-Elsevier Science Ltd, 2026) Ergun, Ece; Halkman, Hilal B. D.; Kasimfirtina, Eren; Kantoglu, Omer; Ergun, Umit; Orhan, Ersin
    This study presents a novel combined treatment process for the decontamination of historical textiles, using gamma irradiation with green antimicrobial agents. Microbiological studies and theoretical approaches were utilized to investigate the effect of treatment processes individually and in combination on isolates from the textile museum. The mean D-10 values and the required doses for complete inactivation were found to be 1.19 and 7.60 kGy for bacteria cocktail and 1.47 and 6.32 kGy for mold cocktail, respectively. The antimicrobial activities of two Schiff bases and their reduced derivatives were tested against gamma-resistant microorganisms by measuring the diameter of the inhibition zones. It was found that reduced derivatives exhibited higher antibacterial activity. All compounds were screened through an in-silico study to evaluate the physicochemical properties, drug-likeness, and toxicity profile. Molecular docking studies were performed to investigate the binding affinity of the title compounds against E. coli DNA gyrase B and topoisomerase IV. From the perspectives of both in vitro studies and computational analysis, L4 exhibited the highest biological activity. This finding revealed that the reduction of the imine bond and molecular flexibility have a significant influence on binding to the active site of the biomolecule. Finally, the combined treatment utilizing L4 with gamma irradiation demonstrated a synergistic effect, leading to a 2.6-fold reduction compared to the control, whereas the individual treatments of L4 and gamma irradiation exhibited approximately a 1-fold reduction. This synergistic effect presents an innovative approach to the historical artifact preservation, providing a more efficient and potentially safer decontamination strategy.