Spectrophotometric determination of drugs with iodine

Abstract

Spectrophotometric method is described for the determination of drugs through charge transfer complex formation with iodine acceptor. This method is based upon molecular interaction between drugs and iodine to form charge transfer complexes in which iodine acts as a sigma acceptor (σ). Iodine was found to form charge transfer complex in 1:1 stoichiometry with all the drugs selected for study. Colored products were quantified spectrophotometrically by using absorption bands. Thermodynamic parameters and spectral characteristics of these complexes have been evaluated. A complete detailed investigation of the formed complex was made with respect to its composition, formation constant and free energy change. Electronic absorption bands are found shifted towards shorter wavelengths upon complex formation with iodine along with well-known blue shift of visible iodine band. The values of formation constants and thermodynamic parameters show a strong donor-acceptor interaction, which helps to study the possible site of interaction between the donors and the acceptors and also provides a tool for the estimation of drugs at both iodine band at 512 <i style="">nm</i> and blue shift band, which are sensitive to the drugs up to the concentration of 10^-3<i style="">M</i>.