Abstract
Kinetics and mechanism of oxidation of carbenicillin by diperiodatocuprate [DPC-III] in aqueous alkaline medium were studied spectrophotometrically at 298 K and an ionic strength of 0.10 mol·dm−3. The reaction between DPC (III) and carbenicillin in the alkaline medium showed (CRBC : DPC-III) 1 : 4 stoichiometry. The reaction products were identified by the CHNS test, FT-IR, and LC-MS spectral reports. The reaction was of pseudo-first order with respect to DPC (III) and fractional order with respect to carbenicillin as well as alkali but retarding effect with respect to periodate. Monoperiodatocuprate (MPC-III) was found to be the main active species in the alkaline medium in the form of [Cu (H2IO6) (H2O)2]. Activation and thermodynamic parameters with respect to uncatalyzed rate constants (ku) and slow step rate constant (k) as well as equilibrium constants were determined. The plausible mechanism consistent with experimental results was proposed and discussed in detail.
Highlights
Penicillanic acid derivatives (PADs) are composed of beta lactam ring and thiazolidine ring as the integral part which have growing demands in daily life, medicines, health tonics, etc. [1]
Carbenicillin, one of the PADs, is the 4th generations’ semisynthetic [2] analogue of naturally occurring benzylpenicillin with carboxyl and benzyl group penicillin which is synthesized from the 6-aminopenicillanic acid nucleus, discovered at Beecham as “Pyopen.” It is active against Pseudomonas aeruginosa in vitro [3] and used successfully in the treatment of pseudomonal infections [4,5,6] due to sensitivities of many strains of P. aeruginosa to carbenicillin within a reasonably narrow range of concentrations which can be safely obtained in vivo [7]
Chemicals used were of Analytical Reagent (AR) grade and double distilled water was used throughout the work. e stock solution of carbenicillin (Sigma Aldrich (0.01 mol·dm−3)) was prepared by dissolving 0.378 g of recrystallized carbenicillin in 100 ml double distilled water
Summary
Penicillanic acid derivatives (PADs) are composed of beta lactam ring and thiazolidine ring as the integral part which have growing demands in daily life, medicines, health tonics, etc. [1]. Penicillanic acid derivatives (PADs) are composed of beta lactam ring and thiazolidine ring as the integral part which have growing demands in daily life, medicines, health tonics, etc. It is an acid liable antibiotic that inhibits bacterial cell wall synthesis and is commonly used in place of ampicillin to reduce the production of satellite colonies. It is more stable than ampicillin at low pH, which usually arises during bacterial fermentation. It is soluble in water (solubility 451 mg/L).
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