ISSN (Print): 2328-3491, ISSN (Online): 2328-3580, ISSN (CD-ROM): 2328-3629 American International Journal of Research in Science, Technology, Engineering & Mathematics AIJRSTEM 13- 215; © 2013, AIJRSTEM All Rights Reserved Page 63 AIJRSTEM is a refereed, indexed, peer-reviewed, multidisciplinary and open access journal published by International Association of Scientific Innovation and Research (IASIR), USA (An Association Unifying the Sciences, Engineering, and Applied Research) Available online at http://www.iasir.net Kinetics and Mechanistic Investigation of Oxidation of Fluoroquinoline Anitibacterial Agent, Norfloxacin, by Diperiodatargentate (III) in aqueous alkaline medium. Heney T Padavathil, Surekha Mavalangi*, S.T.Nandibewoor Department of Engineering Chemistry, The Oxford College of Engineering, Bommanahalli, Bangalore-560 068 I. Introduction: Diperiodatoargentate(III) (DPA) is a powerful oxidizing agent in alkaline medium with the reduction potential[1] 1.74 V. It is widely used as a volumetric reagent for the determination of various organic and inorganic species[2,3]. Jaya Prakash Rao et al.[4,5] has used DPA as an oxidizing agent for the kinetics of oxidation of various organic substrates. They normally found that, order with respect to both oxidant and substrate was unity and [OH-] was found to enhance the rate of reaction. It was also observed that they did not arrive the possible active species of DPA in alkali and on the other hand they proposed mechanisms by generalizing the DPA as [Ag(HL)L] (x+1)- . However, Kumar[6-8] et al. put an effort to give an evidence for the reactive form of DPA in the large scale of alkaline pH. In the present investigation, we have obtained the evidence for the reactive species for DPA in alkaline medium. Norfloxacin, a fluoroquinolone, is a 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3quinolinecarboxylic acid. Its empirical formula is C16H18FN3O3. Norfloxacin is a white to pale yellow crystalline powder with a molecular weight of 319.34 and a melting point of about 221°C. It is freely soluble in glacial acetic acid, and very slightly soluble in ethanol, methanol and water. Norfloxacin is a synthetic chemotherapeutic antibacterial agent[9,10] occasionally used to treat common as well as complicated urinary tract infections. It also inhibits DNA synthesis and is bactericidal[11-16]. Norfloxacin is a first generation synthetic fluoroquinolone (quinolone) developed by Kyorin Seiyaku K.K. It interacts with a number of other drugs, as well as a number of herbal and natural supplements. Such interactions increase the risk of anticoagulation and the formation of non-absorbable complexes, as well as increasing the risk of toxicity. As a result of their extensive usage, fluoroquinolones may enter the environment via wastewater effluent and biosolids from sewage treatment plants and via manure and litters from food-producing animal husbandry. The presence and accumulation of fluoroquinolone antibiotics in aquatic environments, albeit at low concentrations, may pose threats to the ecosystem and human health by inducing increase and spread of bacteria drug resistance due to long-term exposure. This necessitates development of the various advanced oxidation processes for the transformation of fluoroquinolones in water. In view of potential pharmaceutical importance of norfloxacin and lack of literature on the oxidation of this drug by any oxidant except in two cases[17,18] and the complexity of the reaction, a detailed study of the reaction becomes important. The present investigation is aimed at checking the reactivity of norfloxacin toward Diperiodatoargentate (III) and arriving at a plausible mechanism. Abstract:The kinetics and mechanism of oxidation of Norfloxacin (NF) by Diperiodatoargentate (III) (DPA) in alkaline medium at constant ionic strength of 0.10 mol dm -3 was studied spectrophotometrically. The reaction exhibits 1:1 DPA:NF stoichiometry and is first order in DPA but fractional order in both NF and alkali. The order was found to be negative fractional order with respect to periodate. The main reaction products were identified as hydroxilated NF and Ag(I). A mechanism involving free radicals was proposed. In a composite equilibrium step, norfloxacin binds to DPA to form a complex that subsequently decomposes to the products. The reaction was investigated at different temperatures and activation parameters with respect to the slow step of the proposed mechanism were calculated and discussed. Keywords: Norfloxacin, Kinetics, Oxidation, Diperiodatoargentate (III), Reaction Mechanisms.