Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1237843 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2009 | 7 Pages |
The interaction between ketoconazole and povidone drugs with iodine was found to proceed through initial formation of a charge transfer (CT) complex as an intermediate. The stoichiometry of the complex was found to be 1:1 in the case of povidone–iodine system and 1:2 in the case of ketoconazole–iodine system and the same was confirmed by thermal (TGA/DSC) studies. The formation of I3− species was confirmed by electronic and laser Raman spectra. The three peaks appeared in Raman spectra, of the isolated adducts corresponds to νas(I–I), νs(I–I) and δ(I3−), confirmed the presence of asymmetric I3− ion. The rate of the interaction has been measured as a function of time and solvent. The pseudo-first-order rate constants at various temperatures for the interactions were measured and the activation parameters (ΔG#, ΔS# and ΔH#) were computed. Based on the spectral and spectrokinetic evidences a mechanism involving the formation of a polar intermediate and its conversion to the final product has been proposed and discussed.