Comparative Stability of Cephalosporins in Aqueous Solution: Kinetics and Mechanisms of Degradation

Yamana, Tsukinaka; Tsuji, Akira

doi:10.1002/jps.2600651104

Cited by 260 publications

(126 citation statements)

References 31 publications

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“…2). 5 Hydrogen peroxide is used for degradation study in the development of pharmaceuticals. The HCl, NaOH, NH2OH and H2O2 at appropriate concentration were evaluated as degradation agents for cleaning or decontamination.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric Investigation of Oxidation of Cefpodoxime Proxetil by Permanganate in Alkaline Medium: A Kinetic Study

Khan¹,

Mohd²,

Bano³

et al. 2009

Journal of the Korean Chemical Society

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ABSTRACT.A Kinetics pathway of oxidation of Cefpodoxime Proxetil by permanganate in alkaline medium at a constant ionic strength has been studied spectrophotometrically. The reaction showed first order kinetics in permanganate ion concentration and an order less than unity in cefpodoxime acid and alkali concentrations. Increasing ionic strength of the medium increase the rate. The oxidation reaction proceeds via an alkali-permanganate species which forms a complex with cefpodoxime acid. The latter decomposes slowly, followed by a fast reaction between a free radical of cefpodoxime acid and another molecule of permanganate to give the products. Investigations of the reaction at different temperatures allowed the determination of activation parameters with respect to the slow step of proposed mechanism and fallows first order kinetics. The proposed mechanism and the derived rate laws are consistent with the observed kinetics.

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Section: Introductionmentioning

confidence: 99%

Spectrophotometric Investigation of Oxidation of Cefpodoxime Proxetil by Permanganate in Alkaline Medium: A Kinetic Study

Khan¹,

Mohd²,

Bano³

et al. 2009

Journal of the Korean Chemical Society

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“…Nevertheless, the possibility cannot be excluded that the steric bulk (6) of the 6(7)-substituent may decrease (3-lactam ring reactivity through some role other than simply blocking approach to the a face. Also, it should be mentioned that certain cephalosporins with nucleophilic groups on their 7(-acylamido side-chain are known to undergo intramolecular nucleophilic attack on the (3-lactam ring (55)(56)(57)(58) …”

Section: Methodsmentioning

confidence: 99%

Transition state structures of a dipeptide related to the mode of action of beta-lactam antibiotics.

Boyd¹

1977

Proc. Natl. Acad. Sci. U.S.A.

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The tetrahedral adducts formed during nucleophilic attack by a hydroxyl ion on the carbonyl carbon of a model dipeptide, glycylglycine, were studied by modifiedintermediate-neglect-of-differential-overlap molecular orbital calculations. This dipeptide is taken to represent the D-alanyl-D-alanine terminus of the polypeptides involved in the crosslinking transpeptidation reaction of peptidoglycan in bacterial cell walls. It Twelve years ago it was proposed (1) that the fl-lactam antibiotics derive their antibacterial activity because their structure mimics that of a transition state (TS) species formed when a D-alanyl-D-alanine peptide bond is cleaved at the receptor site of a proteolytic enzyme in bacterial cell walls. This idea has remained viable in the light of most subsequent research (e.g., see refs. 2-7 and references cited therein). The final step in cell wall synthesis, the crosslinking of the peptidoglycan strands via a transpeptidation reaction, is the one that is upset by penicillins and cephalosporins. Depending on the organism and the antibiotic, the inhibition can involve a transpeptidase or a carboxypeptidase, be reversible or irreversible, and lead either directly or indirectly to death of growing bacteria (2,4,(8)(9)(10)(11)(12)(13)(14)(15)(16). In bacteria that have been studied (2), the peptidoglycan crosslinks are polypeptides which in their precursor form have. a D-alanyl-D-alanine terminus. Little is known about the structural details of the TSs through which this dipeptide passes. Tipper and Strominger (1) and later Lee (3) noted that a twisting about the peptide C-N bond from the usual trans planar arrangement produces a structure that is more analogous to that of the fl-lactam antibiotics. Because of their bicyclic ring systems, the antibiotics have a CC-NC dihedral angle (corresponding to the CaC'-NCa dehedral angle in a polypeptide) in the range 132°-157°(17). Calculations (3, 5) on the amount of energy this twisting from 1800 requires have shown such structures to be accessible with the energy derivable from the usual sorts of substrate-receptor interactions.In principle, information about the TS structure could be deduced from the three-dimensional arrangement of the functionalities in the receptor site(s) of the relevant enzymes.The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 METHODThe approach was to use the computer as a reaction vessel in which to observe the reactants coming together and starting to react. Quantum mechanical computer calculations for "observing" TSs have the advantage of being able to stop the reaction at any point along the reaction path in order to observe at length species which, experimentally, would be very shortlived and not isolable. The "lens" for this "computer microscope" will be the modified-intermediate-neglect-of-differential-overlap (MINDO/3) molecular orbital (MO) method (22). This method has ...

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“…3 HPLC methods were described for the determination of cefaclor in human plasma and urine. 4,5 Also iodometric 6 and polarographic 7 determination of cefaclor has been reported. A spectrofluorimetric method is described for the determination of cefaclor in formulations and biological fluids.…”

Section: Introductionmentioning

confidence: 99%

Development and application of spectrophotometric method for the determination of cefaclor in pharmaceutical formulations

Raza¹,

Ijaz

Ahmad

2009

Quím. Nova

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Recebido em 18/5/08; aceito em 13/1/09; publicado na web em 28/5/09 A simple, fast and sensitive spectrophotometric method for the determination of cefaclor in pharmaceutical raw and dosage forms based on reaction with ninhydrin is developed, optimized and validated. The purple color (Ruhemenn's purple) that resulted from the reaction was stabilized and measured at 560 nm. Beer's law is obeyed in the concentration range of 4-80 µg mL -1 with molar absorptivity of 1.42 × 10 5 L mole -1 cm -1 . All variables including the reagent concentration, heating time, reaction temperature, color stability period, and cefaclor/ninhydrin ratio were studied in order to optimize the reaction conditions. No interference was observed from common pharmaceutical adjuvant. The developed method is easy to use, accurate and highly cost-effective for routine studies relative to HPLC and other techniques.

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Comparative Stability of Cephalosporins in Aqueous Solution: Kinetics and Mechanisms of Degradation

Cited by 260 publications

References 31 publications

Spectrophotometric Investigation of Oxidation of Cefpodoxime Proxetil by Permanganate in Alkaline Medium: A Kinetic Study

Spectrophotometric Investigation of Oxidation of Cefpodoxime Proxetil by Permanganate in Alkaline Medium: A Kinetic Study

Transition state structures of a dipeptide related to the mode of action of beta-lactam antibiotics.

Development and application of spectrophotometric method for the determination of cefaclor in pharmaceutical formulations

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