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Introduction: Previously, the laparoscopic approach was not considered for obese people, because of the increased risk of operative and postoperative complications. In recent years, however, the approach has changed in favor of minimally invasive procedures that avoid laparotomy, which, in obese people, is the most common cause of complications, in the form of slower and aggravated wound healing, bleeding, and infections at the laparotomy site. In emergency situations, extreme obesity accompanied by multiple comorbidities still remains a real challenge for endoscopic surgery, the surgeon and the entire surgical and anesthesiology team. Case report: We present a case of a 61-year-old, extremely obese patient, who was admitted to hospital as an emergency case, due to prolonged vaginal bleeding and anemia. After preoperative preparation, the patient underwent surgery - laparoscopic total hysterectomy with bilateral salpingo-oophorectomy. Conclusion: Obesity is a major problem in modern society. In addition to directly affecting health, excessive body weight in a patient makes it very difficult to perform surgical procedures. The thickness of the abdominal wall and accompanying health problems are a contraindication for laparoscopic operations. In such cases, performing surgery, especially laparoscopic procedures, requires a trained team of professionals and appropriate equipment. Laparoscopic surgery is more and more present, even in the most difficult cases. In presenting this case, we aimed to demonstrate that it is possible to successfully perform total laparoscopic hysterectomy in extremely obese patients with associated health problems, even in emergency situations.

Placental abruption is defined as the premature separation of the placenta from the uterus. Rapid diagnosis and adequate medical intervention provide a good outcome, which is not possible in all countries. Any bleeding that occurs in the second half of pregnancy raises the suspicion of placental abruption, which is associated with fetal and maternal morbidity and mortality. The clinical picture and consequences for the fetus depend on the degree of bleeding and the amount of blood. Complete abruption leads to the disruption of fetal circulation and oxygenation, asphyxia, and stillbirth. In case of partial abruption, the consequences for the fetus depend on the degree of bleeding. In complete abruption, fetal death is inevitable unless an emergency cesarean delivery is undertaken.

Memantine is a pharmaceutical used to treat memory loss, one of the main symptoms of dementia and Alzheimer’s disease. The use of memantine is expected to continue to grow due to the increasing proportion of the elderly population worldwide. The aim of this work was to conduct a comprehensive study on the behaviour of memantine in the environment and the possibilities of its removal from wastewater. Abiotic elimination processes (hydrolysis, photolysis and sorption) of memantine in the environment were investigated. Results showed that memantine is stable in the environment and easily leached from river sediment. Therefore, further investigation was focused on memantine removal by advanced oxidation processes that would prevent its release into the environment. For photolytic and photocatalytic degradation of memantine, ultraviolet (UV) lamps with the predominant radiation wavelengths of 365 nm (UV-A) and 254/185 nm (UV-C) were used as a source of light. TiO2 in the form of a nanostructured film deposited on the borosilicate glass wall of the reactor was used for photocatalytic experiments. Photodegradation of memantine followed pseudo-first-order kinetics. The half-life of photocatalytic degradation by UV-A light was much higher (46.3 min) than the half-life obtained by UV-C light (3.9 min). Processes degradation efficiencies and evaluation of kinetic constants were based on the results of HPLC-MS/MS analyses, which also enable the identification of memantine oxidation products. The acute toxicity of the reaction mixture during the oxidation was evaluated by monitoring the inhibition of the luminescence of Vibrio fischeri bacteria. The results showed that memantine and its oxidation products were not harmful to Vibrio fischeri.

Pharmaceuticals have special attention of researchers over the world due to their possible effect on the environment and humans. This paper focuses on the photolysis of nitrofurantoin in different water matrices. Nitrofurantoin photodegradation has been indicated as a pseudo-first order photoreaction. The indirect photodegradation rate of nitrofurantoin (river water, k1 = 0.0088 min−1 and synthetic wastewater, k1 = 0.0154 min−1) was slower than its direct photolysis rate (ultrapure water, k1 = 0.0176 min−1). The highest value of quantum yield of nitrofurantoin photodegradation (ϕ = 0.2047) was observed at pH = 4, while at higher pH-values it decreased. Furthermore, the mechanism of nitrofurantoin photodegradation is proposed. Heterocyclic ring opening and further hydrolysis, nucleophilic aromatic photosubstitution and homolytic N–N bond cleavage are suggested as three main initial processes of nitrofurantoin photodegradation. Acute toxicity study of nitrofurantoin and its photoproducts with regard to luminescence inhibition of Vibrio fischeri showed that the toxic effect of nitrofurantoin (EC50 = 4.0 mg L−1) decreases by photolysis.

Ultra-violet light-emitting diode (UV-LED)-based processes for water treatment have shown the potential to surpass the hurdles that prevent the adoption of photocatalysis at a large scale due to UV-LEDs’ unique features and design flexibility. In this work, the degradation of five EU Watch List 2020/1161 pharmaceutical compounds was comprehensively investigated. Initially, the UV-A and UV-C photolytic and photocatalytic degradation of individual compounds and their mixtures were explored. A design of experiments (DoE) approach was used to quantify the effects of numerous variables on the compounds’ degradation rate constant, total organic carbon abatement, and toxicity. The reaction mechanisms of UV-A photocatalysis were investigated by adding different radical scavengers to the mix. The influence of the initial pH was tested and a second DoE helped evaluate the impact of matrix constituents on degradation rates during UV-A photocatalysis. The results showed that each compound had widely different responses to each treatment/scenario, meaning that the optimized design will depend on matrix composition, target pollutant reactivity, and required effluent standards. Each situation should be analyzed individually with care. The levels of the electrical energy per order are still unfeasible for practical applications, but LEDs of lower wavelengths (UV-C) are now approaching UV-A performance levels.

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.

Recent developments in UV-LED technology open up new possibilities for water treatment. TiO2 photocatalysis can benefit from optimized photoreactor design to increase hydroxyl radical production and reduce its electrical energy per order (EEO) demands, which still ranks high among advanced oxidation processes. However, literature on UV-LED photoreactor design is largely lacking. In this work, a detailed investigation of photoreactor design is proposed. The simulation of a lab scale cylindrical reactor with 8 different UV-LED arrays was run with the professional version of an optic software. The increase of radiant flux and irradiance on the reactor’s middle cross section and side walls, respectively, was related to an increasing number of LEDs and to a shorter distance from the reactor but not necessarily to an increase in homogeneity of light distribution. A full factorial experimental design was applied to evaluate the degradation of a representative contaminant of emerging concern (ciprofloxacin) considering 4 independent variables and their interactive effects on kinetic rates and EEO values. The significance of these effects was evaluated with ANOVA and a prediction model was established. The results show that the presence of a TiO2 nanofilm was the most significant tested effect. The number of LEDs, their distance from the reactor’s wall and the adoption of controlled periodic illumination also greatly influenced kinetic rates but were less relevant for reducing EEO values because the energetic trade-off was not sufficient to turn the kinetic gain into lower electricity demands.

The development of ultraviolet light-emitting diodes (UV-LED) opens new possibilities for water treatment and photoreactor design. TiO2 photocatalysis, a technology that has been continuously drawing attention, can potentially benefit from LEDs to become a sustainable alternative for the abatement of organic micropollutants (OMPs). Recently reported data on photocatalytic degradation of OMPs and their parameters of influence are here critically evaluated. The literature on OMP degradation in real water matrices, and at environmentally relevant concentrations, is largely missing, as well as the investigations of the impact of photoreactor design in pollutant degradation kinetics. The key factors for reducing UV-LED treatment technology costs are pointed out, like the increase in external quantum and wall-plug efficiencies of UV-LEDs compared to other technologies, as well as the need for an appropriate design optimizing light homogeneity in the reactor. Controlled periodic illumination, wavelength coupling and H2O2 addition are presented as efficiency enhancement options. Although electrical energy per order (EEO) values for UV-LED photocatalysis have decreased to the range of traditional mercury lamps, values are still not low enough for practical employment. Moreover, due to the adoption of high initial OMP concentration in most experiments, it is likely that most literature EEO values are overestimated. Given the process characteristics, which are favoured by translucent matrices and small diameters for more homogenous light distribution and better transportation of radicals, innovative reactor designs should explore the potential of point-of-use applications to increase photocatalysis applicability at large scale.

Antibiotic pollution is frequently detected in fresh waters and wastewaters where they represent an environ-mental risk for the development of global antibiotic resistance. Due to their excessive use in personal care products, UV filters have also been found to be pseudo-persistent in the aquatic environment. In contrast to antibiotics, which can undergo photodegradation, UV filters are compounds designed to stably absorb UV ra-diation. This study explored the light based remediation of representative antibiotics from seven classes of an- tibiotics (fluoroquinolones, tetracyclines, penicillins, macrolide, glycolpeptide, sulphonamides and trimethoprim) in order to assess whether antibiotic pollution persists longer in the presence of organic UV filters. We show that the presence of UV filters either completely supresses or significantly alters the photodegradation of antibiotics in water. Advanced technologies in wastewater treatment, such as the use of UV C radiation, both effectively minimise the effect of UV filters and degrade most of the tested antibiotics proving to be effective management strategy. However, the half-life of erythromycin and amoxicillin, widely used antibiotics from macrolide- and penicillin-like classes, is extended in the presence of UV filters, even during UV C irradiation. Overall, the UV filters present within environmental mixtures are identified as important drivers of mixture toxicity, as they prolong antibiotic contamination of aquatic and engineered environments. The ramification of such finding is that inadequate consideration of UV filters may result in an imperfect prediction of the solar and UV light-based remediation of antibiotics, lead to improper classification of antibiotics persistence in the envi-ronment and cause non-optimal chemical fate and transport model performance. Use of the more benign com-pounds and assessment of the UV filters were identified as feasible management options in minimizing the influence of UV filters onto the remediation of antibiotics in aquatic environments.

The development of ultraviolet light-emitting diodes (UV-LED) opens new possibilities for water treatment and photoreactor design. TiO

Febantel is an anthelmintic drug active against a range of gastrointestinal parasites in animals. Despite the fact that it has been detected in aquatic environment (water and sediment), there is no information on its fate in the environment. Therefore, we studied abiotic elimination processes of febantel in the aquatic environment. The results of direct and indirect photodegradation experiments showed that febantel was persistent against simulated solar radiation. Hydrolytic elimination kinetics of febantel was dependent on pH and temperature with half-lives in the range from 210 min to 99 days. Febantel metabolites, fenbendazole and fenbendazole sulfon, were identified as major degradation products using high resolution mass spectrometry. The proposed hydrolytic degradation pathway included primarily the base catalyzed hydrolysis and further aromatization as the driving force to imidazole ring of fenbendazole to the related benzo-imidazole derivatives. Aquatic toxicity of febantel and its hydrolytic mixture were evaluated toward the luminescence bacteria Vibrio fischeri. Furthermore, the mechanism and kinetics of sorption, the impact of ionic strength and the influence of pH were examined. Experimental data showed that the best agreement was obtained with the linear model (r2>0.99), while the rate of sorption is the best described with the kinetic model of pseudo-second-order. An elevated level of sorption of febantel onto the sediment was observed with KOC ranged from 1490 L kg-1 to 3894 L kg-1 for five sediment samples with different physicochemical characteristics. Based on the obtained data it could be concluded that febantel is expected to be found predominantly in sediment.

The method for the determination of blue dye Solvent Blue 35 (SB 35) in diesel fuel by high performance liquid chromatography (HPLC) coupled with UV-VIS detection was developed. The dye is separated from the hydrocarbon sample matrix and determined as a single component at 650 nm wavelength. Solid phase extraction (SPE) on the silica based solid phase sorbent was used as a pre-treatment method. Among investigated elution solvent mixtures, the mixture composed of chloroform and heptane in the volume ration of 1:0.75 (v/v) provided the best SB 35 recovery. During method validation two calibration models were tested: external calibration and matrix-matched calibration. For both models correlation coefficients were higher than 0.99 and slopes were compared using the Student's t-test. Precision was evaluated as repeatability and intermediate precision with relative standard deviations less than 7%. Low limit of quantification of 0.1 mg L−1 were obtained. Optimized procedure using 250 mg of sorbens provided recoveries ranged from 76.9% to 99.4% over a linear range (0.1–10 mg L−1). The developed method has been applied to the analysis of blue diesel samples from the market and suspicious samples. The content of SB 35 dye in a commercial blue diesel samples was found to be around 0.5 mg L−1 while presence of SB 35 dye in suspicious sample was confirmed.

Pimavanserin is an atypical antipsychotic indicated for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. As it is a relatively new drug on the market, limited number of pharmacokinetic information and analytical methods are available. This paper presents an ultra-high performance chromatography for the simultaneous determination of pimavanserin and its four process impurities. The method was developed applying analytical quality by design (AQbD) principles as a risk- based approach. Critical method attributes (CMAs) were selected as a resolution between the worst separated compounds (impurity B and impurity C), a duration of analysis defined by the retention time of the last eluting peak (impurity D), a capacity factor of the first eluted impurity (impurity A), a tailing factor and a theoretical plate number. Risk assessment in the early stage of method development pointed out critical method parameters (CMPs): column temperature, gradient time and pH-value of the mobile phase (water phase, eluent A). Design of experiments (DoE), using DryLab®4 software, was applied to evaluate the influence of CMPs on CMAs and to determine method operable design region (MODR). Based on the risk assessment and the results of robustness and precision tests, a control strategy with system suitability criteria was proposed. Developed method was validated according to ICH Q2 (R1) guideline with respect to the selectivity, LOD, LOQ, linearity, precision, accuracy, robustness and stability. A forced degradation study was performed to provide an evidence of the stability-indicating property of the method. Degradation products of pimavanserin were identified using ultra high-performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-qTOF). Additionally, potential degradation products were assessed in silico with the help of Zeneth® software and good agreement with experimentally identified degradation products was achieved. Main degradation products were formed during acid and base hydrolysis (m/z 223.16 [M+H]+ at RRT 0.37) and under oxidative stress conditions (m/z 444.26 [M+H]+ at RRT 0.57). The results revealed that the pimavanserin undergoes degradation through acid and base hydrolysis of urea and N-oxidation of aliphatic tertiary amine.

In this work, a multi-class analytical method for determination of 22 frequently used pharmaceuticals was developed and validated. Analytes were from different classes for example macrolides, fluoroquinolones, tetracyclines, sulfonamides, anthelmintics, anesthetics, and others. Method was intended for analysis of aqueous samples so the sample preparation was done using solid-phase extraction (SPE). Different sorbents (C8, C18, polymeric, and ion exchange sorbents) combining different eluents (methanol, ethanol, acetonitrile, acetone, ethyl acetate) were investigated during development of sample preparation step. Samples were analyzed using HPLC-MS/MS, and therefore, chromatographic and mass spectrometer conditions were investigated. Optimal extraction efficiencies for most of the investigated analytes were obtained with Oasis HLB polymeric sorbents with acetonitrile as eluent. A study of matrix effect was carried out for wastewater treatment plant (WWTP) influent and effluent. The method was validated for linearity, detection limits and quantification limits, repeatability, and reproducibility. Method detection limits were in the range of 2.0-204.0 ng L-1 for WWTP influent except for sulfaguanidine and dexamethasone. Also, method detection limits for WWTP effluent were from 1.0 to 115.4 ng L-1. Method was successfully applied for analysis of real wastewater samples from municipal wastewater treatment plant. In the influent, pharmaceuticals from all investigated groups were present and the concentrations were from 50.0 to 4914.3 ng L-1 for influent and 26.9 to 1699.2 ng L-1 for effluent. It was also reported that some pharmaceuticals showed higher concentrations in the wastewater effluent than in the influent.

In this paper, photolytic and photocatalytic degradation of cephalosporin antibiotic cefdinir dissolved in MilliQ water and in synthetic municipal wastewater are described. Both degradation processes were based on UV-A and UV-C radiation. The UV-A-based oxidation processes have been less efficient in terms of irradiation time required for complete degradation of cefdinir than the UV-C-based processes. The effect of pH value was observed for photocatalytic processes in terms of slower degradation under basic conditions than acidic and neutral conditions. It was also confirmed that different wastewater components could significantly reduce the degradation rate of cefdinir in UV-A-based processes. Although UV-A radiation experiments need more time than UV-C experiments for complete degradation of cefdinir, they have a potential for practical use since such reactor configuration could use natural solar radiation as a source of UV-A radiation and therewith significantly reduce the costs of pharmaceuticals degradation treatment step.

Bez analitičke kemije nemoguće je zamisliti napredak mnogih područja ljudske djelatnosti. Spomenuti značaj ove grane kemije jedan je od glavnih razloga uspješnog opstanka i kontinuiranog razvoja Zavoda za analitičku kemiju unutar jednog tehničkog fakulteta, kao što je današnji Fakultet kemijskog inženjerstva i tehnologije (FKIT) Sveučilišta u Zagrebu. Dinamičnost razvoja analitičke kemije bila je neprestani poticaj nastavnicima Zavoda za prilagođavanjem svjetskim trendovima i sustavnim unaprjeđenjem nastavnog programa i istraživačkog rada. Početak nastavnog, znanstvenog, ali i stručnog djelovanja Zavoda temeljio se na klasičnim metodama analize, no potaknuta razvojem moderne analitičke opreme ubrzo se intenzivirala primjena brojnih kemijskih i fizikalno-kemijskih metoda analize, od kojih je danas najzastupljenija kromatografija. Naime, konac dvadesetog stoljeća ubrzanim je razvojem instrumentalnih tehnika, uvođenjem računala i činjenicom da su podatci analitičkih mjerenja postali temelj odlučivanja u medicini, zaštiti okoliša, razvoju materijala te osiguravanju kvalitete procesa i proizvoda, dao novi uzlet analitičkoj kemiji, a osobit procvat doživjela je kromatografija kao idealna tehnika za višekomponentnu analizu analita u tragovima. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna., Without analytical chemistry, it is impossible to imagine the progress of many areas of human activity. The aforementioned importance of this chemistry branch is one of the main reasons for the successful survival and continued development of the Department of analytical chemistry within a technical faculty, such as is the present-day Faculty of Chemical Engineering and Technology (FCET) University of Zagreb. The dynamics of the development of analytical chemistry was a constant encouragement to the teachers of the Department to adapt to world trends, and systematically improve the curriculum and research work. The beginning of the teaching, the scientific, as well as the professional activities of the Department of Analytical Chemistry was based on classical methods of analysis. However, stimulated by the development of modern analytical equipment, the application of numerous chemical and physicochemical methods of analysis was intensified, of which the most common being chromatography. Namely, the end of the twentieth century accelerated the development of instrumental techniques, the introduction of computers, and the fact that analytical measurement data became the basis of decision-making in medicine, environmental protection, material development, and assuring the quality of processes and products gave rise to analytical chemistry, especially chromatography, which is an ideal technique for multicomponent trace analyte analysis. This work is licensed under a Creative Commons Attribution 4.0 International License.

In this paper, nanostructured TiO2 film was prepared by the by sol-gel process and dip-coating technique with titanium tetraisopropoxide as a precursor. After heat treatment at 550 &deg, C, the deposited film was characterized by means of micro-Raman spectroscopy and atomic force microscopy (AFM). It was found that the TiO2 film consisted of only the TiO2 anatase phase and showed a granular microstructure. Photocatalytic degradation of azithromycin by using sol-gel nanostructured TiO2 film was studied to define the most effective degradation process for potential use in wastewater treatment. Different factors were evaluated during photocatalysis, such as pH (3, 7, and 10), water matrix (ultrapure water and synthetic municipal waste water effluent), influence of another pharmaceutically active compound (sulfamethoxazole, one of the most often detected pharmaceutic compounds in waste waters), and radiation sources (low pressure ultraviolet (UV) mercury lamps with a UV-A and UV-C range, a light-emitting diode (LED) lamp with a radiation peak at 365 nm). The most effective degradation process was achieved with the UV-C irradiation source in matrices at pH 10. The water matrix had little effect on the photocatalytic degradation rates of azithromycin. The presence of sulfamethoxazole in the water matrix decreased the degradation rate of azithromycin, however, only in matrices with a pH level adjusted to 10. During the experiments, five azithromycin degradation products were identified and none of them showed toxic properties, suggesting effective removal of azithromycin. LED 365 nm as the irradiation source was not as effective as the UV-C lamp. Nevertheless, considering the cost, energy efficiency, and environmental aspects of the irradiation source, the LED lamp could be a &ldquo, real-life&rdquo, alternative.

The study explores the potential of immobilized TiO2-based zeolite composite photocatalyst (TiO2- FeZ) made of commercial AEROXIDE TiO2 P25 and iron-exchanged zeolite of ZSM5 type (FeZ), for solar assisted treatment of diclofenac (DCF), pharmaceutical included in the “watch list” during last prioritization in water legislation by EU. In this study the efficiency of applied photocatalytic treatment, solar/TiO2-FeZ/H2O2, of DCF water solution was evaluated on basis of DCF removal and conversion kinetics, as well as the changes of common parameters for assessing water quality. Hence, the changes in the removal and mineralization of overall organic content, biodegradability, toxicity to Vibrio fischeri, dechlorination of DCF and its formed by-products, were monitored during the treatment. The obtained data were correlated with the evolution of DCF by- products, identified and monitored during the treatment by HPLC/MSMS analysis. In order to estimate the influence of water matrix, all experiments were performed in the presence of chloride or sulphate as counter ions. The obtained data revealed that degradation mechanism of DCF by applied treatment process using immobilized TiO2- FeZ includes the adsorption onto photocatalyst surface and consequent degradation. The contribution of homogeneous Fenton reaction due to leached iron ions was found to be negligible. The adsorption and degradation pathway of DCF were influenced by the type of counter ions, which was reflected in the observed changes of water quality parameters.

Farmaceutici su spojevi koji se upotrebljavaju za liječenje ili sprječavanje bolesti ljudi i životinja te kao promotori rasta u veterinarskoj medicini. Posljedica upotrebe farmaceutika je njihova prisutnost u okolišu gdje se zbog različitih fizikalno-kemijskih svojstava vežu na tlo i sediment ili podliježu abiotičkim (hidroliza i fotoliza) ili biotičkim (biološka razgradnja bakterijama i gljivicama) procesima razgradnje. Rezultat navedenih procesa vodi smanjenju koncentracije početne molekule farmaceutika te nastanku novih spojeva koji mogu biti više ili manje stabilni i toksični u odnosu na početnu molekulu farmaceutika. U većini dosadašnjih istraživanja određivane su koncentracije farmaceutika u okolišu, a još uvijek se malo zna o njihovu ponašanju i sudbini u okolišu. Stoga su kroz pojedina poglavlja u ovom radu objašnjeni procesi kojima su farmaceutici podvrgnuti u okolišu. Pharmaceuticals are used for the purpose of preventing or treating diseases in humans and animals, as well as growth promoters in veterinary medicine. The consequence of using pharmaceuticals is their presence in the environment. Once they reach the environment, many processes occur, such as abiotic processes (hydrolysis and photolysis) and biotic processes (biodegradation by bacteria and fungi) or sorption to soil and sediment. These processes lead to the reduction of pharmaceuticals concentration in the environment. Furthermore, the mentioned processes could result in different products that are more or less stable and toxic than the parent compound. Numerous papers have reported the levels of pharmaceuticals in the environment, while little is still known about their behaviour and fate in the environment. Therefore, in this paper, all the mentioned processes are described and discussed.

This paper presents stability study of the nonsteroidal anti-inflammatory drug (NSAID) nepafenac. In order to investigate stability of nepafenac, it was subjected to forced degradation under different stress conditions: acid and base hydrolysis, oxidation, humidity, heat and light. A novel stability indicating reverse phase ultra high performance liquid chromatographic (UHPLC) method coupled to ultraviolet detector has been developed to separate nepafenac and all related compounds (2-aminobenzophenone, Cl-thionepafenac, thionepafenac, Cl-nepafenac, hydroxy-nepafenac, and cyclic-nepafenac). Efficient chromatographic separation was achieved on a Waters Acquity BEH C18 stationary phase with a gradient elution. Quantification was carried out at 235 nm at a flow rate of 0.6 mL/min−1. The resolution between nepafenac and six potential impurities is found to be greater than 2.0. The developed method was validated with respect to specificity, LOD, LOQ, linearity, precision, accuracy and robustness. The r2 values for nepafenac and six potential impurities were all greater than 0.999. The developed method is capable to detect impurities of nepafenac at a level of 0.005% with respect to test concentration of 1.0 mg/mL. Significant degradation is observed in acid, base and oxidative degradation conditions and degradation products (DPs) were identified using mass spectrometry analysis; two of them were found to be a known process related impurities (hydroxy- and cyclic-nepafenac) whereas four degradation products were identified as new degradation impurities. The forced degradation samples were assayed against a qualified reference standard and the mass balance was found to be close to 99.5%.

TiO2 based photocatalytic degradation of nitrofurantion (NFT), a widely used drug, and its primary decomposition products, nitrofuraldehyde (NFA) and aminohydantoin (AHD) was investigated and compared to their photolysis in aerobic systems. UV-vis spectrophotometry, pH, IC, and HPLC measurements were applied to follow the changes during the irradiations and subsequently, in the dark. After a fast anti→syn (or trans→cis) photoisomerization of NFT (giving i-NFT), a slower photohydrolysis of both isomers took place upon UV excitation, leading to the formation of NFA and AHD. i-NFT proved to be more reactive than NFT ; it underwent hydrolysis in the dark, too. While photolysis could not totally convert NFT and i-NFT within 120 min, they disappeared within 90 min during the photocatalysis under the same irradiation conditions, along with the degradation of NFA and AHD, and the accumulation of a rather stable intermediate identified as 5- hydroxyfuran- 2- carbaldehyde, formed from NFA. The direct photolysis of NFA also gave this characteristic intermediate along with its several derivatives formed via addition or condensation then redox transformations. They very slowly decomposed in photolysis, while totally disappeared during photocatalysis of NFA, producing polar aliphatic intermediates. Direct irradiation could not convert AHD, while photocatalysis led to its significant degradation in aerobic system. These results indicate that TiO2 based photocatalysis is suitable for the decomposition and mineralization of NFT and their photoderivatives.

This research deals with photolytic (UV-C (254 nm) and UV-A (365 nm)) and photocatalytic degradation of anthelmintic drug febantel. In photocatalytic experiments TiO2 was used as a catalyst in a form of a nanostructured thin film. UV-C irradiation proved to be effective during photolytic and photocatalytic degradation. The most effective process proved to be photocatalytic degradation with UV-C radiation and febantel half life time was 2.10 min. During the photocatalytic degradation process nine degradation products were detected. High resolution mass spectrometry data were used to propose degradation products structural formulae and corresponding degradation pathways. The main degradation processes are the hydroxylation of the phenyl ring of febantel and methoxyacetamide substituent reduction in febantel. Toxicity of the samples during photocatalysis was investigated using Vibrio fischeri bacteria. Samples showed increase in toxicity as the process advanced which can be attributed to the formation of methyl carbamate derivates as the degradation products.

A determination of the thermodynamic acid dissociation constants (pKa) of 22 frequently used pharmaceuticals using capillary electrophoresis in aqueous media is presented in this work. The investigated pharmaceuticals belong to different pharmacological groups: macrolides, fluoroquinolones, sulfonamides, β-lactams, tetracyclines, and other miscellaneous pharmaceuticals. The electrophoretic mobilities of the investigated analytes were monitored in a pH range from 2.00 to 10.82. The data were fitted with an appropriate mathematical model using a nonlinear regression analysis to obtain pKa values. Experimentally obtained data were well described by the mathematical model chosen for each analyte that was confirmed by r(2) values higher than 0.99 for most of the investigated analytes. Extrapolations to zero ionic strength were used to determine the thermodynamic pKa values. Experimentally obtained acid dissociation constants were interpreted using structural formulae of investigated analytes and the moieties corresponding to specific pKa were identified.

Occurrence of pharmaceuticals, especially antibiotics in the environment increased attention to their environmental fate. Hydrolysis is one of two abiotic processes by which compounds are degraded in the environment. According to authors knowledge this is the first study investigating hydrolytic degradation of nitrofurantoin at pH-values normally found in the environment based on the OECD 111 procedure. Nitrofurantoin hydrolytic degradation appeared to be much slower at acidic (pH 4) solution compared to neutral (pH 7) and alkaline (pH 9) solutions at all three investigated temperatures (20 °C, 40 °C and 60 °C). In all cases nitrofurantoin hydrolysis followed the first- order kinetics with half-lives ranged from 0.5 days at pH 9 and 60 °C to 3.9 years at pH 4 and 20 °C. Temperature dependence of the hydrolysis rate constant was quantified by Arrhenius equation ; obtained Ea values were as follows: 100.7 kJ mol-1 at pH 4, 111.2 kJ mol-1 at pH 7 and 102.3 kJ mol-1 at pH 9. Increase in hydrolysis rate constants for each 10 C increase in temperature were 3.4, 3.9 and 3.5 at pH 4, pH 7 and pH 9, respectively. The structures of hydrolytic degradation products were determined and degradation pathways were suggested. Three main processes occurred depending on pH-values: protonation of the nitrofurantoin followed by cleavage of the N-N single bond, heterocyclic non-aromatic ring cleavage, and reduction of the non-aromatic heterocyclic ring.

Macrolide antibiotics are one of the most prescribed antibiotics in human and veterinary medicine. After administration, they end up in municipal wastewater streams. However, conventional wastewater treatment plants are incapable of removing them effectively resulting in their detection in the discharged effluents and consequently in the environment. Presence of antibiotics in the environmental waters has negative effect on water quality and also contributes to the development of antibiotic resistance. Therefore, advanced treatment methods become an inevitable approach. This mini review provides a brief summary on the occurrence of macrolide antibiotics in the aquatic environment and overview of the recent developments in photocatalytic degradation using TiO 2 for their efficient removal.

The present work describes the development of a sensitive and reliable analytical method based on solid-phase extraction followed by analysis using liquid chromatography with tandem mass spectrometry for the simultaneous determination of pharmaceuticals from antibiotics (fluoroquinolones, sulfonamides, and their N(4)-acetyl metabolites, and trimethoprim as sulfonamides synergist) and anthelmintics groups. SPE was optimized using different cartridges (Strata-X, Oasis HLB, Strata C18 -E, Isolute C18 , SampliQ C8 /Si-SCX). The highest recovery was achieved using Strata X cartridge (>80%) with good reproducibility (RSDs 0.99 for all compounds except for sulfamethazine (0.98). In order to demonstrate the applicability of the developed method, wastewater from the veterinary industry was analyzed. Results evidenced the presence of febantel, praziquantel, albendazole, enrofloxacin, sulfamethazine, and sulfadiazine.

This paper describes the development, optimization, and validation of a method for the determination of five pharmaceuticals from different therapeutic classes (antibiotics, anthelmintics, glucocorticoides) in water samples. Water samples were prepared using SPE and extracts were analyzed by HPLC with diode-array detection. The efficiency of 11 different SPE cartridges to extract the investigated compounds from water was tested in preliminary experiments. Then, the pH of the water sample, elution solvent, and sorbent mass were optimized. Except for optimization of the SPE procedure, selection of the optimal HPLC column with different stationary phases from different manufacturers has been performed. The developed method was validated using spring water samples spiked with appropriate concentrations of pharmaceuticals. Good linearity was obtained in the range of 2.4-200 μg/L, depending on the pharmaceutical with the correlation coefficients >0.9930 in all cases, except for ciprofloxacin (0.9866). Also, the method has revealed that low LODs (0.7-3.9 μg/L), good precision (intra- and interday) with RSD below 17% and recoveries above 98% for all pharmaceuticals. The method has been successfully applied to the analysis of production wastewater samples from the pharmaceutical industry.

Once released into the aquatic environment, pharmaceuticals may undergo different degradation processes. Photodegradation, for example, might be an important elimination process for light-sensitive pharmaceuticals, such as antibiotics. In this study, the fate of sulfonamides (sulfamethazine, sulfadiazine, and sulfamethoxazole) and their N (4)-acetylated metabolites (N (4)-acetylsulfadiazine, N (4)-acetylsulfamethazine, and N (4)-acetylsulfamethoxazole) under simulated sunlight irradiation was investigated. The irradiation resulted in total or almost total degradation (88 to 98 %) of the pharmaceuticals tested, except for sulfamethazine (52 %), during 24 h of irradiation. The photoproducts of all investigated pharmaceuticals have been analyzed using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. Structure elucidation performed from photodegradation products of both, sulfonamides and their N (4)-acetylated metabolites, clearly showed two major formation pathways. These were cleavage of the sulfonamide bond as well as SO2 extrusion. In total, nine photoproducts were elucidated. Among these photoproducts, the tautomers of sulfamethoxazole and desulfonated products of sulfadiazine and sulfamethazine were also present. Tautomers of sulfadiazine and sulfamethazine have been characterized here for the first time as well as some photoproducts of sulfadiazine, sulfametoxazole, and their metabolites N (4)-acetylsulfadiazine and N (4)-acetylsulfametoxazole. The obtained results are an important piece in the complex puzzle for assessing the environmental fate of sulfonamides and their metabolites in the environment.

Dalmatian pyrethrum (Tanacetum cinerariifolium (TREVIR.) SCH.BIP.) is a plant species endemic to the east Adriatic coast. The bioactive substance of Dalmatian pyrethrum is a natural insecticide, pyrethrin, a mixture of six active components (pyrethrins I and II, cinerins I and II, and jasmolins I and II). The insecticidal potential of pyrethrin was recognized decades ago, and dried and ground flowers have traditionally been used in Croatian agriculture and households. A total of 25 Dalmatian pyrethrum populations from Croatia were studied to determine the pyrethrin content and composition, and to identify distinct chemotypes. The total pyrethrin content ranged from 0.36 to 1.30% (dry flower weight; DW) and the pyrethrin I/pyrethrin II ratio ranged from 0.64 to 3.33%. The statistical analyses revealed that the correlations between the percentage of pyrethrin I and of all the other components were significant and negative. The total pyrethrin content was positively correlated with the percentage of pyrethrin I and negatively correlated with cinerin II. The multivariate analysis of the chemical variability enabled the identification of five chemotypes among 25 Dalmatian pyrethrum populations. The chemical characterization of indigenous Dalmatian pyrethrum populations may serve as a good background for future breeding and agricultural exploitation.

Sulfonamides are one of the most frequently used antibiotics worldwide. Therefore, processes that determine their fate in the environment are of great interest. In the present work, biodegradation as biotic process and hydrolysis and photolysis as abiotic processes were investigated. In biodegradation experiments, it was found out that sulfonamides (sulfadiazine and sulfamethazine) and their N4- acetylated metabolites were not readily biodegradable. The results showed that decrease of concentrations were in the range from 4% for sulfadiazine to 22% for N4- acetylsulfamethazine. Hydrolytic experiments examined at pH values normally found in the environment also showed their resistance. However, photolysis proved to be significant process for decreasing concentrations of sulfonamides and their metabolites in three various aqueous matrices (Milli-Q water, river water, and synthetic wastewater). In addition, influence of ubiquitous water constituents (Cl−, NO3−, SO42−, PO43−, and humic acids) was also investigated, showing their different impact on photolysis of investigated pharmaceuticals. The results showed that photolysis followed first-order kinetics in all cases. The obtained results are very important for assesing the environmental fate of sulfonamides and their metabolites in the aquatic environment.

In this study, an anthelmintic drug, praziquantel(PZQ), was degraded using the direct photolysis, photocatalysis, and oxidation processes including UV radiation, TiO2 film, and hydrogen peroxide. The photolytic degradation with predominant wavelengths of 185/254 nm (UV-C) proved to be more efficient with a half-life of 3.13 min compared to the radiation of 365 nm (UV-A) where the degradation did not occur. In order to enhance the rate of PZQ photolytic degradation, H2O2 was added, which resulted in two to three times higher degradation rates. In the photocatalytic degradation, TiO2 film was used as catalyst. The degradation was ten times faster in the photocatalytic experiments where UV-C light (k=0.2390 min-1) was used than in those with UV-A (k=0.0201 min-1). Comparing the results from all performed experiments it can be concluded that the UV-C/TiO2/H2O2 process yielded the highest degradation rate and complete degradation of PZQ was obtained in less than 7 minutes. The degradation of PZQ followed the first order kinetics in all the experiments. The photo degradation was inhibited in the presence of methanol. The degradation pathways and the structural formulae of five degradation products (m/z 273, 269, 189, 147, 132) were proposed based on the liquid chromatography tandem mass spectrometry analysis.

Nepafenac is chemically described as 2-amino-3-benzoylbenzeneacetamide manufactured as a 0.1% suspension for topical ophthalmic use [1] and it belongs to a group of nonsteroidal anti-inflammatory drugs (NSAID). A novel simple, fast and efficient supercritical fluid chromatography (SFC) method was developed and compared with reversed-phase liquid chromatography (RPLC) method for the separation and determination of impurities in Nepafenc [2-3]. Overall satisfactory resolutions and peak shapes for Nepafenac, 2-aminobenzophenone, Cl-thionepafenac, Thionepafenac, Cl-Nepafenac, Hydroxy Nepafenac and Cyclic Nepafenac were obtained by optimization of the chromatography system. With the gradient elution of mobile phase, all of the impurities and the active ingredient were separated within 6 min. Taking full advantage of features of SFC (such as particular selectivity, non-sloping baseline in gradient elution, and without solvent injection effects), the method was successfully used for determination of impurities in Nepafenac. More impurity peaks were detected, better resolution was achieved and much less analysis time was needed in comparison with conventional RPLC methods. The developed SFC method is validated with respect to specificity, LOD, LOQ, linearity, precision, accuracy and robustness.

Today it is well established that the source, presence and the fate of pharmaceutical active compounds in the environment is of concern. This area of research has progressively received more attention as many pharmaceuticals in the environment becomes evident. Once released into the environment, they are transported and distributed into water, sediment, soil and biota. Besides their physical transport in the environment, they are subjected to several other processes that can lead to their elimination in the environment and consequently to a loss of their pharmacological activity. These processes refer to sorption, biodegradation as a biotic process, and non-biotic degradation such as photolysis, hydrolysis and oxidation. The class of compounds, known as the nitrofuran antibiotics are expected to be found in the aquatic environments based on their production and use. Therefore, the aim of this study was to investigate hydrolytic degradation of nitrofurantoin according to the procedure OECD 111. Hydrolysis experiments were performed at three different pH-values, 4.0, 7.0 and 9.0 at three temperatures, 20 °C, 40 °C and 60 °C. In order to determine degradation rate of nitrofurantoin samples were analyzed by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) which was performed with an Agilent 6410 triple-quadrupole mass spectrometer coupled with an Agilent Series 1200 HPLC system.

This special issue contains original research articles on solar energy use for green applications. In particular, the use of solar thermal energy for low environmental impact processes or the use of the light (with or without heterogeneous photocatalysts) for environmental remediation or synthesis was considered. The topic is highly challenging and the subject would be important, timely, and of great interest. Among the submittedmanuscripts, 5 were selected as suitable for publication through the strict experts’ peer reviews.