Isolation and structure elucidation of ampicillin and amoxicillin oligomers

Degradation Pathways of Ampicillin in Alkaline Solutions

“…Oligomers of up to nine units have been reported by different authors (Kuchinskas & Levy 1972;Bundgaard & Larsen 1977;Larsen & Johansen 1982). However, Roets et al (1984) used mass spectrometry to show that ampicillin formed dimers, trimers and tetramers in 20% w/v solutions at pH 8.5 rather than the dimers, tetramers and hexamers previously suggested (Bundgaard & Larsen 1977) on the basis of functional group analysis. These polymers have been found to be present in some clinically used ampicillin solutions (Bundgaard 1978) and are associated with allergic reactions (Larsen & Johansen 1982;Takagi et a1 1983;Urleb et a1 1985).…”

Penicillin degradation catalysed by Zn(II) ions in methanol

“…The common mechanism of hydrolysis has been described by different authors [3][4][5][6]. The ␣-amino penicillins such as ampicillin and amoxicillin can also undergo autoaminolysis in an aqueous solution by means of a nucleophilic attack of the amino group of the lateral chain of a molecule, on the ␤-lactam bond of a second molecule of antibiotic [7][8][9].…”

Thermostability Comparison of Two Solid States of Cefpiramide

“…At the end of the accelerated and stress studies, XRPD was performed to evaluate the structural stability of the different forms, and high molecular mass polymers were also determined since β-lactam antibiotic polymerization is likely to occur under severe conditions (e.g. high temperature) and might cause anaphylaxis in clinical therapy [20][21][22][23]. …”

“…It is of common knowledge that the polymers of β-lactam antibiotics have great impact on the safety of β-lactam antibiotics since they might induce anaphylaxis in clinical therapy [20][21][22][23]. Therefore, at the end of the stability studies, high molecular mass polymers in the samples being examined were analyzed by a validated SEC method (see The Method for High Molecular Mass Polymers) and results are shown in Table 4.…”