Comparison of Influence of Gamma Rays and E-beam on Some Chloramphenicol Derivatives

Ionizing radiation used for sterilization of drugs may lead to drug degradation and therefore essential element of the validation process is the choice of optimal conditions for sterilization, i.e. radiation dose and radiation source. This investigation examines and compares radiostability of derivatives of 1-phenylpropan-1-ol exposed to the same effective doses of ionizing radiation but emitted from different sources: gamma radiation (60Co) and high energy electrons emitted by linear electron accelerator. The drugs used in this investigation were chloramphenicol, its ester (chloramphenicol sodium succinate) and analog (thiamphenicol). It was found that gamma radiation had a more destructive effect on drugs than high energy electrons. This was apparent from the change in the color intensity, increase in the concentration of free radicals, the number of radiolysis products and larger decrease in the drug content. The difference in the power between the two sources of ionizing radiation (1 kGy/h for 60Co and 10 kGy/s for high energy electrons) could account for that.