► Photolysis of a FQs mixture was investigated under simulated solar irradiation. ► Photolysis was investigated in river and synthetic wastewater. ► Pseudo-first order rate constants were determined. ...► FQs photodegradation products were identified based on MS spectra. ► Photodegradation pathways were proposed.
The photolytic degradation of norfloxacin, enrofloxacin and ciprofloxacin, fluoroquinolone antibacterials widely used in human and veterinary medicine, was investigated under simulated solar irradiation in different water matrices (river water and synthetic wastewater similar by composition to wastewater of pharmaceutical industry). The results showed that investigated fluoroquinolones degrade very quickly and photodegradation followed pseudo first order kinetics. The slowest photodegradation rate was observed in river water for all three fluoroquinolones. In the case of pharmaceutical mixture irradiation, no significant differences in rate constants were observed compared to single-component experiments. The structures of photodegradation products were determined and photodegradation pathways were suggested. Two main processes occurred primary from enrofloxacin depending on pH values: (I) cyclopropane ring cleavage at pH 4 and (II) oxidative photodegradation at pH 8. The structures of the photoproducts E-1 to E-6 are unknown and have not been reported for this fluoroquinolone. For ciprofloxacin two main processes were also identified depending on experimental conditions. Under acidic conditions (pH 4), reactions involved rather the quinolone ring (cleavage of the cyclopropane ring and fluorine solvolysis), while at pH 8 the side-chain reactions took place. The photodegradation pathway of norfloxacin somewhat differed from the previous two. There was no significant dependence on reaction conditions and there were no two different pathways. Determination and identification of photodegradation products were performed by liquid chromatography–mass spectrometry (LC–MS/MS). The obtained results are of importance for assessing the environmental fate of fluoroquinolones in aqueous media.
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 N⁴‐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 < 5%) despite various physicochemical properties of the compounds. Investigated analytes were identified and quantitatively determined by liquid chromatography with tandem mass spectrometry using multiple reaction monitoring. The method was shown to be linear over the concentration range of 0.05–30 μg/L for febantel and albendazole, and 0.10–60 μg/L for all other pharmaceuticals. Correlation coefficients were >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.
•Photodegradation of enrofloxacin was performed at two different pH values (4 and 8).•Seven photodegradation products with different molecular weight were identified.•All degradation products were ...removed almost completely (>99%) by RO membranes.•Rejection with loose NF membranes was >92%.
Photolysis in natural aquatic environment might be an important elimination process for the light sensitive antibiotics, such as fluoroquinolones. Photolytic degradation of antibiotics present in wastewaters and natural aquifers can result in generation of new products that may be even more toxic than the parent compound. Therefore, it is important to identify these products and to remove them before entering, for example, drinking water sources, whereby the role of membrane processes is irreplaceable.
In this study photodegradation of enrofloxacin (ENRO) in aquatic media was performed at two different pH values, 4 and 8. Four and three photodegradation products (PDPs) with different molecular weight were identified at pH 4 and 8, respectively. All of them, together with the enrofloxacin as the parent compound were removed almost completely (>99%) by reverse osmosis (RO) and tight nanofiltration (NF) membranes, while by loose NF membranes >92%, except for the smallest PDP with HL membrane (37%) at pH 8. The minimum amount of the compounds in the permeate is the proof that most of the selected RO/NF membranes make an effective barrier for them. The size exclusion was the main rejection mechanism, while the physico-chemical interactions and electrostatic repulsion/attraction probably had influence on the overall rejection by loose NF membranes for the smaller photodegradation products of ENRO.
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.
Farmaceutici u okolišu Periša, Martina; Babić, Sandra
Kemija u industriji,
9/2016, Letnik:
65, Številka:
9-10
Journal Article
Recenzirano
Odprti dostop
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.
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.
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 SO
2
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.
Once released into the environment pharmaceuticals undergo a series of processes leading to their degradation. Photolysis induced by sunlight is the most important way of pharmaceuticals degradation ...in water. In this work the removal of enrofloxacin (ENRO) and its photodegradation products with nanofiltration (NF) and reverse osmosis (RO) membranes was investigated. ENRO solution (10 mg L-1, pH = 8) was irradiated under artificial light for 2 h. As a result the degradation of ENRO produced three photoproducts with molecular weights (MW) 389, 373 and 114 g mol-1. Reverse osmosis (LFC–1, SWC4+) and tight nanofiltration (NF90) membranes almost removed (>99.99%) all the compounds (parent and photodegradation products), but the other nanofiltration (DK, NF and HL) membranes removed more than 92%, with one exception (36.96% for the compound with MW 114 g mol-1) obtained using HL membrane.
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