Electronic, Raman and FT-IR spectral investigations of the charge transfer interactions between ketoconazole and povidone drugs with iodine

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 72; no. 4; pp. 789 - 795
• Main Authors: Pandeeswaran, M., Elango, K.P.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.05.2009
• Subjects: Anti-Infective Agents, Local - chemistry; Charge transfer; Electrochemistry; Iodine - chemistry; Iodine and Solvent effect; Ketoconazole; Ketoconazole - chemistry; Molecular Structure; Povidone; Povidone - chemistry; Solvents - chemistry; Spectrokinetic; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Povidone; Iodine and Solvent effect; Spectrokinetic; Ketoconazole; Charge transfer
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2008.11.020

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 I 3 − species was confirmed by electronic and laser Raman spectra. The three peaks appeared in Raman spectra, of the isolated adducts corresponds to ν as(I–I), ν s(I–I) and δ(I 3 −), confirmed the presence of asymmetric I 3 − 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.