Browsing by Author "Mete, Cihat"

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Development of a Novel Electrochemical Method for the Quantitative Analysis of Vandetanib in the Presence of Anionic Surfactant Utilizing a Bare Carbon Paste Electrode
(Marmara Univ, 2024) Pinar, Pinar Talay; Mete, Cihat; Senturk, Zuhre
In this investigation, a novel electrochemical approach employing a bare carbon paste electrode (CPE) has been devised for the sensitive and expeditious quantification of the tyrosine kinase inhibitor vandetanib (VAN). VAN, a pivotal anti-tumor agent employed in various cancer types, notably medullary thyroid cancer, manifested an irreversible oxidation peak at approximately +1.17 V (vs. Ag/AgCl, 3 M NaCl) in 0.1 M HNO3, 3 , elucidated through cyclic voltammetry. The electrode reaction was determined to proceed via controlled adsorption. The study meticulously examined the influence of anionic surfactant sodium dodecyl sulfate (SDS), instrumental parameters, pH fluctuations, and the composition of the supporting electrolyte on the oxidation peak of VAN. Remarkably, the sensitivity of stripping voltammetric measurements markedly augmented upon the inclusion of 9 x 10-4 - 4 M SDS. Employing optimized parameters for SW-AdSV (square-wave adsorptive stripping voltammetry), the bare CPE demonstrated exceptional linearity within the dynamic ranges of 1.05x10-7 - 7 - 1.6x10-5 - 5 M for VAN. The limit of detection and limit of quantification were established at 2.7x10-8 - 8 and 9.0x10-8 - 8 M for VAN, respectively. Furthermore, the developed electrochemical methodology was effectively applied for the detection of VAN in spiked model serum samples.
Electrochemical Determination of Anti-Cancer Drug Dabrafenib With High Sensitivity Using Multi-Walled Carbon Nano Tubes Modified Glassy Carbon Electrode
(Wiley-v C H verlag Gmbh, 2024) Mete, Cihat; Pinar, Pinar Talay
Dabrafenib (DAB) is an organofluor compound and a protein kinase inhibitor used as the mesylate salt in the treatment of metastatic melanoma. For the first time, the electrochemical investigation of the anticancer drug DAB in human serum was conducted using a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs), employing cyclic voltammetry and square wave voltammetry (SWV) techniques. Electrochemical impedance spectroscopy, cyclic voltammetry, and scanning electron microscopy (SEM) techniques were utilized to analyze the surface morphology and structure of the MWCNT/GC electrode. In the proposed method using optimized experimental conditions, two different linearities were obtained for DAB in the concentration range of 0.04-0.8 mu M and 1.0-10.0 mu M. The LOD value obtained is 0.014 mu M. In this study, the resulting electrochemical sensor was applied for the first time to investigate the electrochemical behavior of DAB with high sensitivity and reproducibility, as well as the possible electrochemical oxidation mechanism. Dabrafenib, a organofluor compound and a protein kinase inhibitor, was electrochemically analyzed for the first time on a MWCNT-modified GCE, proposing an oxidation mechanism. Surface morphology and structure were examined using electrochemical impedance spectroscopy, cyclic voltammetry, and scanning electron microscopy. The electrode reaction was irreversible and diffusion-controlled, accompanied by a -2e-/2H+ oxidation reaction. Under optimized experimental conditions, two different linear ranges were obtained for DAB in 0.2 M H2SO4 solution, ranging from 0.04 to 0.8 mu M and 1.0 to 10.0 mu M, with a LOD value of 0.014 mu M. This developed method was applied to biological samples. image
Using a Boron-Doped Diamond Electrode in Anionic Surfactant Media as an Improved Electrochemical Sensor for the Anticancer Drug Ibrutinib
(Wiley-v C H verlag Gmbh, 2023) Mete, Cihat; Pinar, Pinar Talay
The electrochemical properties of ibrutinib (IBR), a new generation smart anti-cancer drug, one of the Bruton's tyrosine kinase (BTK) inhibitors were investigated by a voltammetric method in the anionic surfactant (sodium dodecyl sulfate, SDS) medium with the boron-doped diamond electrode (BDDE). IBR showed an oxidation step at about +1.56 V (vs Ag/AgCl (3.0 mol L-1 KCl) by cyclic voltammetry (CV) technique in 0.1 mol L-1 H2SO4 solution. IBR was found to be irreversible and diffusion-controlled on the surface of the BDDE with studies of scan rate. The possible electrochemical oxidation reaction of IBR with the electroactive ring (pyrazole-pyrimidine ring) in the structure of IBR is discussed. Square wave voltammetry (SWV) was preferred as the study method due to reproducibility for the determination of IBR in pharmaceutical and urine samples. At optimal values of SWV parameters, IBR showed good linearity in the concentration range of 0.01-2.00 mu g mL(-1) (5.7x10(-8)-2.3x10(-6) mol L-1) in 0.1 mol L-1 H2SO4 with 6x10(-4) M SDS. The detection (LOD) and quantification (LOQ) limits for IBR were set at 0.003 mu g mL(-1) (6.9x10(-9) mol L-1) and 0.01 mu g mL(-1) (2.27x10(-8) mol L-1), respectively. The relative standard deviation of the intra-day and inter-day repeatability of the proposed method was found 2.15 and 3.76, respectively. The necessary validation parameters have also been studied, and the recovery results obtained from both pharmaceutical dosage form and human urine samples show that the developed method is accurate and precise.
Voltammetric Determination of Ibrutinib Active Substance Used in Cancer Treatments
(2023) Mete, Cihat; Pınar, Pınar Talay
Bu tez çalışmasında, bruton tirozin kinaz (BTK) inhibitörlerinden yeni nesil akıllı bir antikanser ilaç olan ibrutinib (IBR)'in, elektrokimyasal özellikleri, bor katkılı elmas (BDD) elektrot ile anyonik bir yüzey aktif madde (sodyum dodesil sülfat, SDS) ortamında voltametrik bir yaklaşım kullanılarak incelenmiştir. IBR, dönüşümlü voltametri (CV) tekniği kullanılarak 0.1 mol L-1 H2SO4 çözeltisinde yaklaşık +1.56 V'ta (Ag/AgCl'ye karşı (3.0 mol L-1 KCl) bir yükseltgenme piki göstermiştir. IBR'nin tarama hızı çalışmalarıyla geri dönüşümsüz ve difüzyon kontrollü olduğu tespit edilmiştir. IBR'in potansiyel elektrokimyasal yükseltgenme reaksiyonu IBR'nin yapısındaki elektroaktif halkaya (pirazolpirimidin halkası) bağlı model yapılarıyla ilişkisi araştırılmıştır. Farmasötik ve idrar örneklerinde IBR tayini için hassas bir teknik olması nedeniyle çalışma yöntemi olarak kare dalga voltametrisi (SWV) tercih edilmiştir. IBR, uygun SWV parametre değerlerinde 0.01-2.00 μg mL-1 (5.7×10-7-2.3×10-6 mol L-1) konsantrasyon aralığında 0.1 mol L-1 H2SO4 içinde 6×10-4 mol L-1 SDS varlığında iyi doğrusallık göstermiştir. IBR için LOD (gözlenebilme sınırı) ve LOQ (tayin sınırı) sınırları sırasıyla 0.003 μg mL-1 (6.9×10-9 mol L-1) ve 0.01 μg mL-1 (2.27×10-8 mol L-1) olarak belirlenmiştir. Önerilen yöntemin gün içi ve günler arası tekrarlanabilirliğinin sırasıyla 2.15 ve 3.76 bağıl standart sapmaya sahip olduğu bulunmuştur. En iyi deney koşulları altında hem farmasötik dozaj formundan hem de insan idrar örneklerinden elde edilen geri kazanım bulguları, tasarlanan yöntemin doğruluğunu ve kesinliğini göstermiştir.