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Pharmaceuticals as ubiquitous organic pollutants in the aquatic environment represent substances whose knowledge of environmental fate is still limited. One such compound is metoclopramide, whose direct and indirect photolysis and toxicological assessment have been studied for the first time in this study. Experiments were performed under solar radiation, showing metoclopramide as a compound that can easily degrade in different water matrices. The effect of pH-values showed the faster degradation at pH = 7, while the highly alkaline conditions at pH = 11 slowed photolysis. The highest value of quantum yield of metoclopramide photodegradation (ϕ = 43.55·10−4) was obtained at pH = 7. Various organic and inorganic substances (NO3−, Fe(III), HA, Cl−, Br−, HCO3−, SO42−), commonly present in natural water, inhibited the degradation by absorbing light. In all experiments, kinetics followed pseudo-first-order reaction with r2 greater than 0.98. The structures of the photolytic degradation products were tentatively identified, and degradation photoproducts were proposed. The hydroxylation of the aromatic ring and the amino group's dealkylation were two major photoproduct formation mechanisms. Calculated thermochemical quantities are in agreement with the experimentally observed stability of different photoproducts. Reactive sites in metoclopramide were studied with conceptual density functional theory and regions most susceptible to •OH attack were characterized. Metoclopramide and its degradation products were neither genotoxic for bacteria Salmonella typhimurium in the SOS/umuC assay nor acutely toxic for bacteria Vibrio fischeri.

The pharmaceutical industry routinely performs stability testing on new compounds before they are marketed to ensure their efficacy, quality, and safety. The focus of this study was to apply forced degradation as one of the stability testing methods to investigate the stability of crizotinib, an anticancer drug, and to gain insight into the degradation pathway and degradation products formed. The forced degradation study for crizotinib was performed under acidic and alkaline hydrolysis, oxidation, photolysis and thermal conditions. Drug degradation was observed under oxidative conditions. The structures of the three major degradation products formed by oxidative degradation were identified and characterized by UHPLC/QTOF/MS/MS studies and their possible fragmentation pathways were suggested. The toxicity evaluation of the tested compound and its proposed degradation products was also estimated using the computer program TEST (Toxicity Estimation Software Tool). This work is licensed under a Creative Commons Attribution 4.0 International License.

Ciprofloxacin is a fluoroquinolone antibiotic that is effective in vitro against Gram- positive and Gram-negative microorganisms. Since the ciprofloxacin, along with other pharmaceuticals, can influence the environment, the goal of this study was to examine the possibility of ciprofloxacin removal from water using biosorbents, an unconventional and cheaper subclass of adsorbents. For this purpose, the effect of ionic strength, pH, temperature, different mass of the used biosorbent, and physical- chemical characteristics of biosorbents on ciprofloxacin sorption was investigated. Biosorbents, used in this study, are the various waste products like maple leaves (ML), tangerine peel (TP), and tomato waste (TW) (seeds and peel). Sorption parameters of ciprofloxacin were determined by linear, Freundlich, and Dubinin-Radushkevich isotherms. The highest value of the sorption coefficient, Kd, shows the maple leaves, while the minimum achieves a sample of tangerine peel. These values correspond to the analysis and distribution of pore size, where the tangerine peel sample has the lowest specific surface area. The obtained results indicated the potential of investigated biosorbents to sorption of ciprofloxacin, which ultimately can contribute to environmental protection and the disposal of waste products.

Nitrofurantoin is nitrofuran antibacterial drug that is most used as a veterinary pharmaceutic compound. This compound, as well as other pharmaceuticals can greatly affect the environment, the soil and organisms in it and pollute aquatic ecosystems. Since it has been used for only a few decades, knowledge of their fate and behaviour in the environment is still limited. Because of that, the aim of this study was to experimentally determine the Kd values of nitrofurantoin in seven different natural soil and seven different sediment samples with different physico-chemical properties. Sorption phenomena were described with Linear, Freundlich and Dubinin-Radushkevich sorption isotherms. Obtained sorption coefficients (Kd) ranged from 3.967 to 5.121 mLg−1 for sediment samples and 3.634–43.06 mL g−1 for soil samples. The influence of ionic strength and pH of the nitrofurantoin solution and kinetics of the sorption and desorption process were also investigated. Results show that an increase in ionic strength and pH reduces the values of sorption coefficient while the mechanism of nitrofurantoin sorption is the best described with the kinetic model of pseudo-second order.