Department of Analytical Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt.
Department of Analytical Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Sep 5;202:401-409. doi: 10.1016/j.saa.2018.05.062. Epub 2018 May 19.
Charge-transfer complex (CTC) formation between tioconazole (TCZ) as an n-electron donor and 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ) as a π-acceptor was studied spectrophotometrically with an accompanying kinetic and thermodynamic investigation. Multivariate data analysis via a set of experimental designs was executed for this purpose. A 2 - two-level full factorial design (FFD) was used for inspecting the proposed variables while a face-centered central composite design (FCCCD) was used to adjust the levels of variables proved to be significant. Two responses were quantified as a result of this interaction; complex I (Y1, measured at 743 nm) and complex II (Y2, measured at 842 nm). Derringer's function and overlaid contour plots were used to concurrently optimize both responses. Benesi-Hildebrand equation was applied to determine of formation constant (K), and the molar absorptivity (Ɛ) of the formed complex. Different thermodynamic parameters; the standard Gibbs free energy change (∆G°), the standard enthalpy of formation (∆H°) and the standard entropy change (∆S°) were determined for the reaction product. The proposed method was validated regarding the linearity, intra-, and inter-day precision and accuracy, limit of detection, limit of quantification and following the ICH standards. The proposed method was also applied for the determination of TCZ in its pharmaceutical preparations. Having a higher molar absorptivity and higher formation constant, complex II was of choice for all subsequent measurements. Application of Benesi-Hildebrand equation supported the formation of 1: 1 CTC. Thermodynamic study revealed the endothermic characters and the spontaneity of formation of the CTC at high temperature.
采用分光光度法，伴随动力学和热力学研究，研究了噻康唑（TCZ）作为 n-电子供体与 7,7,8,8-四氰基对醌二甲烷（TCNQ）作为π-受体之间的电荷转移配合物（CTC）的形成。为此目的，通过一组实验设计执行了多元数据分析。使用 2-两水平完全因子设计（FFD）检查建议变量，而使用面心中央复合设计（FCCCD）调整被证明是重要的变量水平。该相互作用产生了两个响应；复合物 I（Y1，在 743nm 处测量）和复合物 II（Y2，在 842nm 处测量）。Derringer 函数和叠加等高线图用于同时优化两个响应。应用 Benesi-Hildebrand 方程确定形成常数（K）和形成的配合物的摩尔吸光系数（Ɛ）。确定了反应产物的不同热力学参数；标准吉布斯自由能变化（∆G°），标准生成焓（∆H°）和标准熵变化（∆S°）。该方法在 ICH 标准范围内，针对线性、日内和日间精密度和准确度、检测限、定量限进行了验证。该方法还用于其药物制剂中 TCZ 的测定。复合物 II 的摩尔吸光系数较高且形成常数较高，因此是所有后续测量的首选。Benesi-Hildebrand 方程的应用支持 1:1 CTC 的形成。热力学研究表明，在高温下 CTC 的形成是吸热的，并且是自发的。
