Usefulness of charge–transfer complexation for the assessment of sympathomimetic drugs: Spectroscopic properties of drug ephedrine hydrochloride complexed with some π-acceptors

摘要: Abstract Recently, ephedrine (Eph) assessment in food products, pharmaceutical formulations, human fluids of athletes and detection drug toxicity abuse, has gained a growing interest. To provide basic data that can be used to Eph quantitatively based on charge–transfer (CT) complexation, the CT complexes with 7′,8,8′-tetracyanoquinodimethane (TCNQ), dichlorodicyanobenzoquinone (DDQ), 1,3-dinitrobenzene (DNB) or tetrabromothiophene (TBT) were synthesized spectroscopically investigated. The newly have been characterized via elemental analysis, IR, Raman, 1 H NMR, UV–visible spectroscopy. formation constant ( K ), molar extinction coefficient e ) other spectroscopic determined using Benesi–Hildebrand method its modifications. sharp, well-defined Bragg reflections at specific 2 θ angles identified from powder X-ray diffraction patterns. Thermal decomposition behavior these was also studied, their kinetic thermodynamic parameters calculated Coats–Redfern Horowitz–Metzger equations.