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Radiation induced degradation of doxazosin

Pharmaceuticals are widely consumed in modern societies and after use active agents and their metabolites can enter the environment via different pathways [1]. Due to high stability of pharmaceuticals in water and incomplete removal during conventional wastewater treatment processes some pharmaceuticals end up in the environment mainly in surface waters, groundwater and also in drinking water. The presence of pharmaceuticals in the aquatic environment may have adverse effects on human health which include aquatic toxicity, development of pathogenic bacteria, genotoxicity and endocrine disrupter [1, 2]. Doxazosin (DOX), a selective alpha blocker, is widely used in medical therapy as an effective antihypertensive agent. The degradation scenario of DOX under TiO2 photocatalytic conditions, as one of the AOP processes, together with the degradation mechanism and toxicity of photoproducts have been studied recently [3]. In the present work we have focused on the degradation of doxazosin in aqueous solution by gamma irradiation. The efficiency of degradation was studied under different absorbed doses, dose rates, pH values and in the presence of radical scavengers and inorganic ions. The irradiated samples were analyzed by UV/VIS spectrophotometry and high performance liquid chromatography with diode array detector. The results indicate that •OH are the main reactive species responsible for the degradation of doxazosin, the efficiency of degradation being higher with increasing dose of gamma radiation (Figure 1.). The presence of nitrates had a stronger effect on doxazosin degradation compared to carbonates and phosphates. An optimal pH for doxazosin degradation was in the neutral, slightly acidic range (pH = 6.5), while degradation was slower under extremely acidic or alkaline conditions.

gamma irradiation ; pharmaceuticals ; doxazosin ; wastewater

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