چکیده (انگلیسی):

Three charge transfer complexes of azelastine as n-donor with p acceptors, dichlorodicyanobenzoquinone
(DDQ), chloranilic acid (CA) and tetracyanoquinodimethane (TCNQ) were
prepared in acetonitrile. They yield a radical anions measured at 456, 520 and 841 nm within concentration
ranges of 8.0–72, 40–320 and 1.6–14.4 lg mL1 with good correlation coefficients
(r =0.9996–0.9998). The molar absorptivities and association constants for the colored products
were evaluated using the Benesi–Hildebrand equation. The free energy change (DG0) and the
enthalpy of formation (DH0) as well as the entropy (DS0) were determined for the reaction product
with TCNQ. The methods were successfully applied to the analysis of azelastine in its pharmaceutical
preparations, where no interferences could be observed from the additives commonly present
in the eye drops or nasal spray as proved by good mean recoveries of 98.89 ±1.06–99.54 ± 1.84%.
The results were compared, favorably with the manufacturer method and validated according to
ICH guidelines.