The Influence of Oxygen and Nitrogen on the Radiolysis of Chloramphenicol

Abstract

This study investigates the influence of oxygen and nitrogen on the radiolysis of chloramphenicol (CAP). The drug substance was irradiated with 25, 50 and 100 kGy (60Co-source) under nitrogen, oxygen and ambient atmosphere, respectively. The content and the impurity profile of CAP were determined with several analytical methods. The content was determined by HPLC as well as by DSC. No significant (p = 95%) difference was found between CAP irradiated under oxygen and nitrogen atmosphere. Purity analysis of CAP was determined by liquid chromatography and by two thin-layer chromatographic systems. Nitrogen was found to act as a scavenger. Several degradation products decreased under nitrogen atmosphere. Oxygen neither increased the sum of impurities significantly nor induced any new radiolytical products. Furthermore, oxygen also showed a scavenging effect. The extent of the radiolysis of CAP (0.5–1.0%) was on an acceptable level. The known impurities 4-nitrobenzaldehyde and 4-nitrobenzoic acid amounted to less than 0.10%. AMPD and two further known impurities were above a threshold of 0.1 %.

Keywords

• Chloramphenicol
• Gamma-irradiation
• Nitrogen
• Oxygen
• Pharmaceutical chemistry
• Scavenger