The photostability of olanzapine, recently most commonly used atypical antipsychotic agent, was investigated. Two irradiation sources were applied, namely solar simulated light (E= 250 and 500 W/m(2)) and monochromatic ultraviolet light (lambda = 254 and 366). The olanzapine adsorption on a titanium dioxide surface was confirmed by differential scanning calorimetry and infrared spectroscopy. Kinetic studies were performed on a basis of a spectrophotometric method. Degradation efficiency was assessed by applying high performance liquid chromatography with an ultraviolet detection. HPLC analysis did not show any degradation products. Olanzapine was found to degrade under photocatalytic conditions with the creation of low molecular products. Disappearance of olanzapine from titanium dioxide surface after degradation was confirmed by IR spectra. A simple and promising way to apply the photocatalytic removal of olanzapine in titanium dioxide suspension was presented. (C) 2012 Elsevier B.V. All rights reserved.