Study on the charge-transfer reaction between 7,7,8,8-tetracyanoquinodimethane and drugs

The charge-transfer (CT) reaction between 7,7,8,8-tetracyanoquinodimethane (TCNQ) as a x-electron acceptor and cinnarizine, analgin, norfloxacin as el ectron donors have been studied by spectrophotometric method. The charge tr ansfer complexes between TCNQ and these drugs have stable blue color, there fore a simple, rapid, accurate and sensitive method for determination of th ese drugs has been developed. The optimization of the experimental conditio ns is described. Beer's law is obeyed in the ranges 2-18, 2-18 and 4-32 mu g/ml for cinnarizine, analgin and norfloxacin, respectively. The apparent m olar absorptivity of CT complexes at 743 nm is 1.58 x 10(4), 1.71 x 10(4) a nd 8.91 x 10(3) l/mol per cm, respectively. The composition of all these CT complexes are found to be 1:1 by different methods. The relative SDs are l ess than 3% (n = 10). The proposed method has been applied to the determina tion of these drugs in their each pharmaceutical dosage forms with satisfac tory results. (C) 1999 Elsevier Science B.V. All rights reserved.