Electron Paramagnetic Resonance investigations of ultraviolet irradiated prednisone

Electron Paramagnetic Resonance or Electron Spin Resonance is a spectroscopic technique that can be successfully applied to measure and characterize the concentration of radiation induced radicals or compounds with one or more unpaired electron from organic and inorganic materials [1]. We have studied the behaviour of the ultraviolet light- induced free radicals in powder samples of prednisone [C 21 H 26 O 5 or 17, 21- dihydroxy pregna-1, 4-diene-3, 11, 20-trione] in order to observe the effects of ultraviolet and light radiation both in drug and in its active substance. The prednisone has not Electron Paramagnetic Resonance signal before ultraviolet irradiation, but after the nonionizing radiation type exposure the relative yielding of free radicals depends on the irradiation time.