Influence of the UV-Vis irradiation on the acute toxicity to zebrafish and mutagenicity of the selected psychotropic drugs

The influence of the UV-Vis radiation on the toxicity of agomelatine, loxapine, clozapine and tiapride was studied. The phototransformation procedure was conducted with the use of simulated solar radiation. In the case of each compound irradiation time necessary to decompose half of the initial concentration was chosen. The embryotoxicity and acute toxicity were evaluated using zebrafish (Danio rerio) embryos and larvae. The mutagenicity assay was done with the use of a micro-plate Ames test. Generally, the embryotoxicity decreased after the irradiation procedure. The obtained results showed that tiapride is the least toxic compound to zebrafish, however, its toxicity toward larvae increases after the irradiation. Similarly, the mutagenic potential of the mixture of tiapride photoproducts is higher than in the case of parent compound. The phototransformation of loxapine resulted in the change of the acute toxicity profile and increased the rate of reverse mutations in the Ames test. Oppositely, the irradiation of agomelatine caused the decrease of mutagenic potential and acute toxicity was also lower in the postirradiated mixture. The phototransformation of clozapine did not alter the mutagenicity and decreased the acute toxicity to the zebrafish larvae. In silico calculations showed a satisfactory prediction ability in some instances, especially in the case of mutagenic potential of the tiapride phototransformation products.

Applicability evaluation of advanced processes for elimination of neurophysiological activity of antidepressant fluoxetine

Presence of the antidepressant fluoxetine in different water bodies has raised significant concerns due to its detrimental effects on non-targeted organisms, especially on fish. When seeking for an appropriate technology able to remove fluoxetine residue from a complex water matrix, special attention needs to be paid to the elimination of the neurophysiological activity that eventually lies behind the noxious effects of the parent compound. Our aim was to probe the applicability of advanced oxidation techniques for this purpose using in situ generated free radical system based on OH-initiated peroxyl radical-mediated processes. By performing product analysis experiments along with quantum chemical calculations, the most probable reaction paths were analyzed including aromatic hydroxylation, defluorination, O-dealkylation and C-dealkylation. The candidates for neurophysiological activity were further investigated by molecular docking. The hydroxylated derivatives are well accommodated in the binding pocket of the corresponding protein, suggesting that these compounds may retain the activity of the parent compound. From a worst-case perspective, we suggest that prolonged treatment needs to be applied to further transform hydroxylated derivatives.

Photolytic and photocatalytic degradation of tandospirone: Determination of kinetics, identification of transformation products and in silico estimation of toxicity

The photolytic and photocatalytic transformation of tandospirone with the use of TiO₂ and H₂O₂ was investigated. A micro-scale method for simultaneous irradiation with simulated full solar spectrum of multiple samples in photostability chamber was proposed. RP-UHPLC-DAD coupled with ESI-Q-TOF mass spectrometer was used for the quantitative and qualitative analysis of the processes. The developed method was fully validated and the kinetic parameters of tandospirone photodegradation were compared. The structures of eighteen photoproducts as well as phototransformation pathways were proposed. Based on the elucidated structures, computational toxicity assessment with the use of various software was performed and most of the photoproducts were found as less or similarly toxic to the parent compound. Nevertheless, several products, including one of the drug main metabolites, were significantly more toxic than the parent drug. The multivariate chemometric method (principal component analysis) was used to compare the toxicity of phototransformation products as well as the toxicity of the assessment methods.

Studies on photodegradation process of psychotropic drugs: a review

Consumption of psychotropic drugs is still increasing, especially in high-income countries. One of the most crucial consequences of this fact is significant release of them to the environment. Considerable amounts of atypical antipsychotics, benzodiazepines, antidepressants, and their metabolites were detected in river, lake, and sea water, as well as in tissues of aquatic organisms. Their ecotoxicity was proved by numerous studies. It should be noticed that interaction between psychotropic pharmaceuticals and radiation may lead to formation of potentially more toxic intermediates. On the other hand, photo-assisted wastewater treatment methods can be used as an efficient way to eliminate them from the environment. Many methods based on photolysis and photocatalysis were proposed and developed recently; nevertheless, the problem is still unsolved. However, according to recent studies, photocatalysis could be considered as the most promising and far more effective than regular photolysis. An overview on photolytic as well as homogenous and heterogeneous photocatalytic degradation methods with the use of various catalysts is presented. The photostability and phototoxicity of pharmaceuticals were also discussed. Various analytical methods were used for the photodegradation research, and this issue was also compared and summarized. Use of high-resolution multistage mass spectrometry (Q-TOF, ion trap, Orbitrap) was suggested. The combined techniques such as LC-MS, GC-MS, and LC-NMR, which enable qualitative and quantitative analyses in one run, proved to be the most valuable in this case. Assembling of MS/MS spectra libraries of drug molecules and their phototransformation products was identified as the future challenge.

Enhanced Ga2O3-photocatalyzed and photochemical degradation of the Fipronil insecticide by UVC irradiation in mixed aqueous/organic media under an inert atmosphere

The water-insoluble insecticide Fipronil can be easily mineralized by gallium oxide catalysis in aqueous organic media (ethanol or methanol etc.) under a nitrogen atmosphere under UVC irradiation (254 nm).

Efficient halogen photoelimination from dibromo, dichloro and difluoro tellurophenes

Visible light induces photoreductive elimination of bromine, chlorine, and for the first time, fluorine from the tellurium center of 2,5-diphenyltellurophene.

Photochemical and Ga2O3-photoassisted decomposition of the insecticide Fipronil in aqueous media upon UVC radiation

Fipronil is degraded photolytically and photocatalytically (β-Ga₂O₃ and TiO₂) in aqueous media under UVC illumination and under reductive and oxidative conditions.