Synthesis, spectroscopic characterization and structural investigation of new charge-transfer complexes of piroxicam with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and chloranilic acid: Experimental and theoretical studies

2019 ◽  
Vol 9 (3) ◽  
pp. 203-212
Author(s):  
Armağan Kinal ◽  
Merve Güreşci ◽  
H. AIRrabiah ◽  
H. A. Abdel-Aziz ◽  
G. A. E. Mostafa
Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.


2016 ◽  
Vol 8 (3) ◽  
pp. 1745-1753
Author(s):  
F. Ibrahim ◽  
N. El-Enany ◽  
Sh. Shalan ◽  
Rasha Mostafa Elsharawy

Two simple, accurate and sensitive spectrophotometric methods were carried out to investigate through charge-transfer reactions of risperidone (RIS) as n-electron donor with various π acceptors: 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ) and p-chloranilic acid (pCA). The absorbance of reaction product was measured at 842 and 520 nm for TCNQ and pCA reagents respectively. Different experimental parameters affecting the reactions were carefully studied. The reaction pathway was postulated. The proposed spectrophotometric method was utilized for the analysis of RIS in pure form as well as in its pharmaceutical preparations. Under the optimum reaction conditions, Beer’s law is obeyed over the concentration range of 1-12 µg mL-1 and 10-180 µg mL-1 for TCNQ and pCA respectively. The limit of assays detection (LOD) is 0.114 µg mL-1 and 2.55 µg mL-1 for TCNQ and pCA respectively. The mean recovery percentage was 99.72 ± 1.06 and 100.50 ± 1.07 for TCNQ and pCA respectively. The results were compared favorably with those obtained by comparison method. The proposed method was validated statistically according to ICH guidelines.


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