TITLE:
Spectrophotometric Determination of Lamivudine Using Chloranilic Acid and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)
AUTHORS:
Kenneth C. Madu, P. O. Ukoha, A. A. Attama
KEYWORDS:
Charge-Transfer Complexation, Chloranilic Acid, DDQ, Lamivudine, Spectrophotometric Determination, Thermodynamic Studies, pH, Pharmaceutical Formulation
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.2 No.7,
November
3,
2011
ABSTRACT: A spectrophotometric method for the assay of lamivudine in pure form and in dosage form was developed in this study. The method was based on charge-transfer complex formation between the drug, which acted as n-donor while chloranilic acid and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) acted as a p-acceptor in a non-aqueous solvent in each case. Chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometry with lamuvudine (lamivudine-chloranilic acid) with a maximium absorption band at 521 nm. Also, DDQ was found to form a charge-transfer complex in a 1:1 stoichiometry with lamivudine (lamivudine-DDQ) with a maximium absorption band at 530 nm. The pH was obeyed at acid range. The complexes obeyed Beer’s law at a concentration range of 0.04 - 0.28 mg/ml. The thermodynamic parameters calculated at different temperatures included the molar absorptivity, association constant, free energy change, enthalpy and entropy. The proposed method has been conveniently applied in the analysis of commercially available lamivudine tablet with good accuracy and precision.