studies on the charge-transfer interaction between tamoxifen citrate and chloranilic acid

the complex formed as a consequence of the interaction between the electron-acceptor p-chloranilic acid and an electron donor tamoxifen citrate was employed in the assay of the drug in pure powder and tablets. chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometric ratio, with tamoxifen citrate. the wavelength of maximum absorption for the complex was found to be 550 nm while the absorbance was linear over the concentration range of 2-100 g/ml. evaluations of the various thermodynamic parameters by means of the scott equation was carried out and were found to decrease with increase in temperature. the free energy change ( g°) and the enthalpy of formation ( h°) as well as the entropy ( s°) were determined for various interactions. results obtained suggest that the proposed method may be conveniently applied in the analysis of commercially available tamoxifen citrate tablets with a high degree of accuracy and reproducibility.