Alkaline degradation of clavulanic acid and high performance liquid chromatographic determination by post-column alkaline degradation.

Publisher Website
Google Scholar
Abstract
Alkaline degradation of clavulanic acid [a bacterial .beta.-lactamase inhibitor] in methanol and in aqueous solution was investigated. Potassium clavulanate was degraded in methanol and in NaOH-saturated methanol to yield methyl 8-hydroxy-6-oxo-4-aza-2-octenoate (1), which showed UV absorption with maximum absorbance at 268 nm (methanol). The UV absorption of 1 almost disappeared in acidic conditions and reappeared on subsequent realkalization, suggesting interconversion between 1 and its protonated form. Potassium clavulanate might be rapidly hydrolyzed in alkaline aqueous solutions to 8-hydroxy-6-oxo-4-aza-2-octenoic acid (2), which has strong UV absorption at .apprx. 260 nm. The acid-base interconversion was also observed between (2) and its protonated form, the latter exhibiting almost no UV absorption at .apprx. 260 nm. An ion-pair reversed-phase high performance liquid chromatography method with the alkaline degradation reaction incorporated into post-column was developed for the determination of clavulanic acid in plasma and urine. After separation from regular components of plasma and urine, clavulanic acid was degraded in NaOH solution in a reaction coil followed by detection of the UV absorbance of the degradation product at 270 nm. The procedure was quantitative over a wide range of clavulanic acid concentration in plasma and urine down to 0.1 .mu.g/ml.

This publication has 1 reference indexed in Scilit: