ISSN:
1612-1112
Keywords:
Column liquid chromatography
;
Ion-pair and GPC separations
;
Amoxicillin oligomers
;
β-Lactam ring polymers
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Summary Polymeric substances formed from concentrated sodium amoxicillin in an aqueous solution have been separated using two high-performance liquid chromatographic methods. We used a C18 reversed-phase column with tetrabutylammonium chloride as an ion-pairing agent with an acetonitrile gradient and a TSKgel G2500PWxl column with water as the solvent for gel permeation chromatography. The separated materials, ranging in size from the monomer to the tetramer, have been characterized by functional-group chemical analysis, while the identification of the piperazine-2,5-dione was done using a pure standard. A greater number of peaks which were also better defined were obtained using the ion-pair reversed-phase method, and open and closed beta-lactam ring polymer forms could be distinguished. Using the gel permeation method, only a few monomer, piperazine-2,5-dione, dimer, trimer and combined amoxicillin trimer and tetramer peaks were obtained with water, although those obtained were quite well defined. The data on the time-course of formation of the oligomers and the amoxicillin degradation product were virtually identical by both methods.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02267799
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