Investigation of a proposed penicillin G acidic degradation scheme using high-pressure liquid chromatography and optimization techniques and mechanistic considerations

Kessler, David P.; Cushman, Mark; Ghebre-Sellassie, Isaac; Knevel, Adelbert M.; Hem, Stanley L.

doi:10.1039/p29830001699

Cited by 17 publications

(12 citation statements)

References 2 publications

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“…It is now available for intramuscular and intravenous injection. The acid stability of aminopenicillin over other types of penicillin has been attributed to the incorporation of an electron withdrawing substituent (NH 2 ) on its side chain (Kessler et al 1983). It also influences the stability of amoxicillin under neutral and alkaline conditions (Van Krimpen et al 1987;Robinson-Fuentes et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Kinetic studies of the degradation of an aminopenicillin antibiotic (amoxicillin trihydrate) in aqueous solution using heat conduction microcalorimetry

Chadha

Kashid

Jain

2003

Journal of Pharmacy and Pharmacology

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Recent developments in isothermal microcalorimetry allow the direct determination of kinetic and thermodynamic parameters for slow reactions from studies conducted at appropriate temperatures and under designated environmental control. The degradation kinetics of amoxicillin trihydrate has been investigated as a function of pH (1-10) and temperature (303.15-318.15 K) at 0.5 M ionic strength using heat conduction microcalorimetry. Equations were developed incorporating calorimetric accessible data, rate constants and change in enthalpy, which showed that the degradation of amoxicillin trihydrate in aqueous solution followed pseudo-first-order kinetics under our experimental conditions. The enthalpy of degradation reaction was found to be exothermic in nature. The values of the rate constant k for individual steps were determined from the values of the overall rate constants at different pH. Energy of activation of overall reaction as a function of pH and for individual rate constants was determined. The log k-pH profiles indicated specific-acid and specific-base catalysis and there were inflection points near pH 3 and pH 7 corresponding to the pKa1 and pKa2 values. Quantitatively, there was good correlation between calorimetric determined half-life (t1/2) and the literature value in the acidic region determined by other methods at 310.15 K. The presence of a beta-lactam ring and of an alpha-amino group in the C-6 side chain played a critical role in the degradation of amoxicillin trihydrate and the zwitterionic form of the drug was found to be more stable.

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Section: Introductionmentioning

confidence: 99%

Kinetic studies of the degradation of an aminopenicillin antibiotic (amoxicillin trihydrate) in aqueous solution using heat conduction microcalorimetry

Chadha

Kashid

Jain

2003

Journal of Pharmacy and Pharmacology

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“…At high concentration (75%), ampicillin became unstable and it decomposed to conjugated forms such as penicilloic acid, penilloic acid, and 2-Hydroxy-3-phenylpyrazine. [46][47][48] HPLC analysis ( Supplementary Fig. 4) of 1-month-old 75% ampicillin-PEDOT:PSS confirmed this possible polymerization/conjugated forms.…”

Section: Concentration-dependent Chemical Interactions Of Ampicillinmentioning

confidence: 56%

“…The ampicillin chemical structure 46,47 contains an electrophile -NH 2 (primary amine) group, secondary amine, nucleophile -C = O, and a lactam ring (tertiary amine) ( Supplementary Fig. 3).…”

Section: Concentration-dependent Chemical Interactions Of Ampicillinmentioning

confidence: 99%

The effect of introducing antibiotics into organic light-emitting diodes

et al. 2019

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The quest to improve the performance of organic light-emitting diodes (OLEDs) has led to the exploration of new materials with properties like interfacial dipole, excitons generation, and bandgap alignment. Here, we exploit these strategies by investigating the interaction of the antibiotic ampicillin with a widely used optoelectronic material, to fabricate state-of-theart OLEDs. The charge distribution on the ampicillin molecule facilitates the generation of an interfacial dipole with a large magnitude. The optimum fusion of the two materials provides an enhanced bandgap alignment, charge balance and J/H-aggregated excitons. Values of current efficiency (120 cdA −1), external quantum efficiency (~35%) and power efficiency (70 lmW −1) are demonstrated. The cross-evaluation of performance with penicillin devices indicates the significance of ampicillin's specific molecular structure in improving performance. The detailed investigations demonstrate that ampicillin has superior optoelectronic properties with high potential to contribute extensively in OLEDs and photovoltaics.

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“…The proportion of each product formed depends upon the pH [59,60]. Although several kinetic studies have been reported on the degradation of penicillins in acidic media [61][62][63][64] there is still uncertainty about the details of the reaction pathway. It has been proposed [31,63] that an oxazolone-thiazolidine intermediate, formed by nucleophilic attack of the acylamido side-chain on the b-lactam carbonyl carbon, is the precursor of the degradation products.…”

Section: Acid Hydrolysismentioning

confidence: 99%

“…However, epimerization then occurs at C(5) to give a mixture of the (5R,6R)-and (5S,6R)-penicilloic acids (17) [64,[130][131][132][133]. The equilibrium constant for the ratio of the (5S,6R)-to that of the (5R,6R)-benzylpenicilloate is 4.…”

Section: Epimerizationmentioning

confidence: 99%

Structure and Reactivity of β‐Lactams

Page

2010

Amino Acids, Peptides and Proteins in Organic Chemistry

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Investigation of a proposed penicillin G acidic degradation scheme using high-pressure liquid chromatography and optimization techniques and mechanistic considerations

Cited by 17 publications

References 2 publications

Kinetic studies of the degradation of an aminopenicillin antibiotic (amoxicillin trihydrate) in aqueous solution using heat conduction microcalorimetry

Kinetic studies of the degradation of an aminopenicillin antibiotic (amoxicillin trihydrate) in aqueous solution using heat conduction microcalorimetry

The effect of introducing antibiotics into organic light-emitting diodes

Structure and Reactivity of β‐Lactams

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