EPR and UV-Vis Spectroscopic Studies of the Influence of Ultraviolet Irradiation on Antioxidant Interactions of Nystatin

Abstract

The changes of the free radical scavenging activity of nystatin after UV-irradiation were examined. The kinetics of the interactions of nystatin with free radicals was tested. The model DPPH free radicals were used. Free radicals were tested by an X-band (9.3 GHz) electron paramagnetic resonance spectroscopy. The EPR spectra of DPPH and DPPH in contact with non-irradiated and UV-irradiated nystatin were measured. Nystatin quenched the EPR spectra of DPPH free radicals as the result of the antioxidative character of the samples. The antioxidative character of non-irradiated and UV-irradiated nystatin was confirmed by the UV-Vis studies. Free radical scavenging activity decreased after UV-irradiation of nystatin and the EPR spectra of DPPH free radicals lower decreased by contact with UV-irradiated nystatin. The quenching of UV-Vis spectra were lower for UV-irradiated nystatin than for than with non-irradiated drug. It was pointed out that nystatin should not be storage under ultraviolet irradiation, because of decrease its antioxidative interactions. This studies confirmed usefulness of EPR spectroscopy and UV-Vis spectrophotometry to determine of the antioxidant character of drugs. These spectroscopic methods may be used to find the optimal storage conditions of drugs.

Influence of Storage Conditions on the Stability of Gum Arabic and Tragacanth

“…Proper storage conditions are a very important aspect that affects the action and stability of the active pharmaceutical substance (API), and excipients used in pharmacy. Physical factors such as temperature, UV radiation, or moisture may adversely affect the stored pharmaceutical preparation [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. As a result of the higher temperature, chemical bonds may be broken in the thermolysis process, which leads to the degradation of the stored substance [ 1 , 2 , 3 ].…”

“…As a result of the higher temperature, chemical bonds may be broken in the thermolysis process, which leads to the degradation of the stored substance [ 1 , 2 , 3 ]. As a result of exposure to UV radiation, energy quanta may be absorbed by the chemical substance, which may lead to its destruction in the process of photolysis [ 4 , 5 , 6 ]. In addition, improperly selected air moisture during the storage of API or excipients may also adversely affect the stability of the chemical substance [ 7 , 8 , 9 ].…”