Abstract

DEGRADATION OF PENICILLIN G AND PENICILLIN V IN AQUEOUS SOLUTION BY ?-LACTAMASE

Lixin Li, Chunhai Guo, Lianfeng Ai and Hanwen Sun*

ABSTRACT

The enzymatic degradation of penicillin G and penicillin V in aqueous solution was investigated by ultra-performance liquid chromatography coupled with electrospray ionization-time-of-flight mass spectrometry. Their degradation products were identified based on the accurate mass and a sub-structure of penicillin. The influence factors on the degradation was investigated, including β-lactamase dosage, tempera ture, time, and acidity. The effect of pH and temperature on enzymatic degradations and degraded products of penicillin is stronger than on chemical acid hydrolysis. Penicilloic acid was the dominant species obtained at pH 7 under 30°C, but, being unstable, it could not be used as a standard for accurate analysis of penicilloic acid. Penilloic acid was the dominant species obtained at pH 2 above 30°C, being stable, so it may be used as a standard for quantitative analysis.

Keywords: Penicillin G, penicillin V, degradation, ?-lactamase.