Identification, characterization and suppression of side-products formed during the synthesis of high dose 68Ga-DOTA-TATE.

In the course of the establishment of (68)Ga-DOTA-TATE production for clinical use a shoulder comprising presumably several impurities was observed in the chromatogram of the analytical radio-HPLC. LC-MS/MS results support the hypothesis that some of these radioimpurities are radiolytic oxidation by-products of (68)Ga-DOTA-TATE. A new HPLC method was developed for quality control of (68)Ga-DOTA-TATE. Significant improvement on the radiochemical purity of (68)Ga-DOTA-TATE was achieved by the addition of ascorbic acid or ethanol to the reaction mixture.

Environmental risk assessment of ivermectin: A case study.

The veterinary parasiticide ivermectin was selected as a case study compound within the project ERAPharm (Environmental Risk Assessment of Pharmaceuticals). Based on experimental data generated within ERAPharm and additional literature data, an environmental risk assessment (ERA) was performed mainly according to international and European guidelines. For the environmental compartments surface water, sediment, and dung, a risk was indicated at all levels of the tiered assessment approach. Only for soil was no risk indicated after the lower tier assessment. However, the use of effects data from additional 2-species and multispecies studies resulted in a risk indication for collembolans. Although previously performed ERAs for ivermectin revealed no concern for the aquatic compartment, and transient effects on dung-insect populations were not considered as relevant, the present ERA clearly demonstrates unacceptable risks for all investigated environmental compartments and hence suggests the necessity of reassessing ivermectin-containing products. Based on this case study, several gaps in the existing guidelines for ERA of pharmaceuticals were shown and improvements have been suggested. The action limit at the start of the ERA, for example, is not protective for substances such as ivermectin when used on intensively reared animals. Furthermore, initial predicted environmental concentrations (PECs) of ivermectin in soil were estimated to be lower than refined PECs, indicating that the currently used tiered approach for exposure assessment is not appropriate for substances with potential for accumulation in soil. In addition, guidance is lacking for the assessment of effects at higher tiers of the ERA, e.g., for field studies or a tiered effects assessment in the dung compartment.

Environmental fate of the anthelmintic ivermectin in an aerobic sediment/water system.

This study investigated the long-term fate of (3)H-ivermectin and its metabolites in aerobic sediment/water systems. Total radioactivity in sediment and water was measured by Liquid Scintillation Counting and Radio-HPLC was used for determination of transformation products. The test system, containing a cooling and a water trap, showed excellent applicability for studying environmental fate of (3)H-labelled compounds. A complete mass balance was obtained over the whole duration with total recoveries ranging from 91.3% to 98.8%. In water, a DT(50)-value of ivermectin of <6h and a DT(90)-value of 16.8 d were obtained. The DT(50)-value of ivermectin in the entire system was 127 d. Maximum distribution coefficients were calculated to K(d)=160 L kg(-1) and K(oc)=3550 L kg(-1). The fraction of bound residues increased to a maximum percentage of 30.4% after 188 d. In total about 31.3% of the initially applied ivermectin were transformed after 188 d. Two transformation products ivermectin monosaccharide and ivermectin aglycone, could be identified in samples from day 100 and 188, respectively. However, additional peaks which were observed in the radio-chromatograms indicate that several other transformation product are formed.

Transformation of the X-ray contrast medium iopromide in soil and biological wastewater treatment.

In water/soil systems, the iodinated contrast medium iopromide was quantitatively biotransformed into several transformation products (TPs). Twelve TPs were identified via HPLC-UV and LC tandem MS. The chemical structures of the TPs were elucidated via fragmentation in MS2 and MS3 of LC tandem MS with a linear ion trap and 1H and 13C NMR analyses. All TPs exhibited transformations at the side chains containing either carboxylic moieties and/or primary and secondary amide moieties, while the triiodoisophthalic acid structure remained unaltered. A transformation pathway was proposed based on the sequence of TP formation in aerobic batch experiments. Additionally, the occurrence of iopromide TPs was investigated in native water samples. All TPs identified were found in municipal WWTP effluents because of their formation during biological wastewater treatment with maximum concentrations of up to 3.7 +/- 0.9 microg/L (TP 819). Predominantly, those TPs were present at higher concentrations in WWTP effluents which were formed at the beginning of the transformation pathway. Furthermore, four TPs formed at the end of the transformation pathway (TP 759, 701A/B, and 643) were also found in bank filtrate up to 0.050 microg/L and in groundwater of an wastewater irrigation area up to 4.6 microg/L.

Decarbonylation of multi-substituted [18F]benzaldehydes for modelling syntheses of 18F-labelled aromatic amino acids.

For 18F-labelling of aromatic amino acids such as tyrosine and DOPA simple and efficient procedures have been under development for quite a while. The direct introduction of 18F using [18F]fluoride can principally be realized by nucleophilic aromatic substitution (SNAr). However, this requires the presence of an appropriate leaving group and an auxiliary substituent, which is able to reduce the electron density of the benzene ring. Furthermore, this auxiliary substituent should be removable easily after the introduction of 18F. The electron-withdrawing formyl substituent meets both requirements. It facilitates nucleophilic attack in the ortho and/or para position and is easily removed in a decarbonylation reaction mediated by Wilkinson's catalyst (RhCl(PPh3)3). In order to evaluate the reaction conditions for a possible synthesis of 2-[18F]fluoro-5-hydroxyphenylalanine ([18F]-m-tyrosine), 2-[18F]fluoro-4-hydroxyphenylalanine ([18F]-p-tyrosine) or 2-[18F]fluoro-4,5-hydroxyphenylalanine ([18F]FDOPA), the dependence of the decarbonylation reaction on solvent, temperature, reaction time and catalyst concentration was studied using appropriate model compounds. Optimum yields of 81%, 89% and 88% could be achieved using benzonitrile as solvent and 2M equivalents of RhCl(PPh3)3 (based on labelling precursor) at 150 degrees C reaction temperature within 20 min reaction time for compounds modelling [18F]-m-tyrosine, [18F]-p-tyrosine and [18F]FDOPA, respectively.

Simultaneous determination of psychoactive drugs and their metabolites in aqueous matrices by liquid chromatography mass Spectrometry.

A multi-residue method was developed that allows for the simultaneous determination of psychoactive compounds such as opioids, tranquilizers, antiepileptics (primidone, carbamazepine plus two metabolites),the cocaine metabolite benzoylecgonine, the antidepressant doxepin, as well as the calcium channel blocker verapamil in raw and treated wastewater, surface water, groundwater, and drinking water. After solid-phase extraction with Oasis HLB at neutral pH, the analytes were detected by LC electrospray tandem MS in the positive ion mode. With a few exceptions relative recoveries of the analytes exceeded 70%. The limits of quantification were in the low ng/L range. Matrix effects were compensated by using appropriate deuterated or 13C-15N-labeled surrogate standards. For raw and treated wastewater, concentration factors were lowered to reduce matrix effects. Most analytes (15 of 20) were found in raw and treated wastewater as well as in surface water, and hence, are presumably ubiquitously present in the environment. Antiepileptics, the opium alkaloids morphine and codeine, dihydrocodeine, the two tranquilizers oxazepam and temazepam, the opioid tramadol, doxepin, and verapamil were detected in STP discharges and German rivers at concentrations up to the microg/L range. In drinking water, only carbamazepine, its metabolite 10,11-dihydroxy-10,11-dihydrocarbamazepine, and primidone were present at concentrations up to 0.020 microg/L.

Biological degradation of pharmaceuticals in municipal wastewater treatment: proposing a classification scheme.

A simple classification scheme is suggested to characterize the biological degradation of micropollutants such as pharmaceuticals, musk fragrances and estrogens during wastewater treatment. The scheme should be a basis for the discussion about potential removal efficiencies. Hence, the biological degradation of 25 pharmaceuticals, hormones and fragrances was studied in batch experiments at typical concentration levels using activated sewage sludge originating from nutrient-eliminating municipal wastewater treatment plants. Since pseudo first-order degradation kinetics was observed for all compounds down to ng L(-1) levels, the removal rates can be predicted for various reactor configurations. Therefore dilution of wastewater (e.g. by extraneous water) is expected to reduce the degree of biological removal. Wastewater segregation and treatment at the source are therefore to be favoured for elimination of persistent micropollutants over centralized end-of-pipe treatment. For reactor configurations typical for nutrient removal in municipal wastewater, the derived formula for predicting removal allows the identification of three groups of micropollutants according to their degradation constant k(biol): compounds with k(biol)<0.1 L g(SS)(-1)d(-1) are not removed to a significant extent (<20%), compounds with k(biol)>10 L g(SS)(-1)d(-1) transformed by >90% and in-between moderate removal is expected. Based on the degradation of a heterogeneous group of 35 compounds (including literature data), state of the art biological treatment schemes for municipal wastewater are not efficient in degrading pharmaceuticals: only 4 out of 35 compounds are degraded by more than 90% while 17 compounds are removed by less than 50%.

Environmental fate of pharmaceuticals in water/sediment systems.

In recent years there has been growing interest on the occurrence and the fate of pharmaceuticals in the aquatic environment. Nevertheless, few data are available covering the fate of the pharmaceuticals in the water/sediment compartment. In this study, the environmental fate of 10 selected pharmaceuticals and pharmaceutical metabolites was investigated in water/sediment systems including both the analysis of water and sediment. The experiments covered the application of four 14C-labeled pharmaceuticals (diazepam, ibuprofen, iopromide, and paracetamol) for which radio-TLC analysis was used as well as six nonlabeled compounds (carbamazepine, clofibric acid, 10,11-dihydro-10,11-dihydroxycarbamazepine, 2-hydroxyibuprofen, ivermectin, and oxazepam), which were analyzed via LC-tandem MS. Ibuprofen, 2-hydroxyibuprofen, and paracetamol displayed a low persistence with DT50 values in the water/sediment system < or =20 d. The sediment played a key role in the elimination of paracetamol due to the rapid and extensive formation of bound residues. A moderate persistence was found for ivermectin and oxazepam with DT50 values of 15 and 54 d, respectively. Lopromide, for which no corresponding DT50 values could be calculated, also exhibited a moderate persistence and was transformed into at least four transformation products. For diazepam, carbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine, and clofibric acid, system DT90 values of >365 d were found, which exhibit their high persistence in the water/sediment system. An elevated level of sorption onto the sediment was observed for ivermectin, diazepam, oxazepam, and carbamazepine. Respective Koc values calculated from the experimental data ranged from 1172 L x kg(-1) for ivermectin down to 83 L x kg(-1) for carbamazepine.

Extraction and determination of sulfonamides, macrolides, and trimethoprim in sewage sludge.

Pressurized liquid extraction (PLE) was optimized and validated for the determination of sulfonamide and macrolide antimicrobials and trimethoprim in sewage sludge samples. A mixture of water/methanol (50:50, v/v) was found as the most efficient extraction solvent. A temperature of 100 degrees C and a pressure of 100 bar were chosen for extraction. Two cycles of 5 min each efficiently extracted at least 97% of the total extractable amount of all studied analytes from activated sludge. The limits of quantification (S/N= 10) varied between 3 and 41 microg/kg dry weight (dw) and the relative recoveries ranged between 78 and 142%. Additionally, the influence of pH and different LC/MS/MS systems on the absolute recoveries was assessed. Of the investigated antimicrobials sulfapyridin, sulfamethoxazole, trimethoprim, azithromycin, clarithromycin and roxithromycin were detected in municipal sewage sludge samples. Concentrations in activated sludge ranged up to 197 microg/kgdw. In comparison, results obtained by ultrasonic solvent extraction were significantly lower for sulfonamides and in tendency lower for macrolides.

Oxidation of pharmaceuticals during ozonation of municipal wastewater effluents: a pilot study.

To reduce the release of pharmaceuticals and endocrine disruptors into the aquatic environment or to remove them from wastewater intended for direct or indirect reuse, the application of advanced wastewater treatment may be required. In the present study, municipal wastewater effluents were treated with ozone (O3) in a pilot-scale plant consisting of two bubble columns. The investigated effluents, which varied in suspended solids concentrations, comprised an effluent of conventional activated sludge treatment (CAS), the same effluent dosed with 15 mg of TSS L(-1) of activated sludge (CAS + SS), and the effluent of a membrane bioreactor pilot plant (MBR). Selected classes of pharmaceuticals were spiked in the wastewater at realistic levels ranging from 0.5 to 5 microg L(-1). Samples taken at the inlet and the outlet of the pilot plant were analyzed with liquid chromatography (LC)-electrospray tandem mass spectrometry (MS). Macrolide and sulfonamide antibiotics, estrogens, and the acidic pharmaceuticals diclofenac, naproxen, and indomethacin were oxidized by more than 90-99% for O3 doses > or = 2 mg L(-1) in all effluents. X-ray contrast media and a few acidic pharmaceuticals were only partly oxidized, but no significant differences were observed among the three effluents. These results show that many pharmaceuticals present in wastewater can be efficiently oxidized with O3 and that suspended solids have only a minor influence on the oxidation efficiency of nonsorbing micropollutants.

Determination of pharmaceuticals, iodinated contrast media and musk fragrances in sludge by LC/tandem MS and GC/MS.

Analytical methods have been developed that allow for the determination of antiphlogistics, lipid regulators, the antiepileptic carbamazepine, cytostatic agents, the psychiatric drug diazepam and iodinated contrast media (ICM) as well as two major polycyclic musk fragrances HHCB (galaxolide) and AHTN (tonalide) in activated and digested sludge. The procedures consist of ultrasonic solvent extraction (USE) using methanol/acetone or pressurized liquid extraction (PLE) using 100% methanol. Clean-up was performed with C18ec material and silica gel followed by LC tandem MS (electrospray or atmospheric pressure chemical ionization) detection for pharmaceuticals and iodinated contrast media as well as GC/MS in the SIM mode for musk fragrances. Absolute recoveries from spiked activated sludge in general ranged from 88+/-4 to 119+/-20% for ICM and were 78+/-15 and 87+/-10% for the AHTN and HHCB, respectively. For the pharmaceuticals, absolute recoveries in activated sludge ranged between 43 and 78%. Subsequently, compensation of losses was carried out by using surrogate standards (acidic pharmaceuticals: fenoprop, neutral pharmaceuticals: dihydro-carbamazepine, musk fragrances: AHTN-D3). With one exception the recoveries were also adequate in digested sludge ranging from 43% to 120%.

Impact of antibiotics on conjugational resistance gene transfer in Staphylococcus aureus in sewage.

The growing rate of microbial pathogens becoming resistant to standard antibiotics is an important threat to public health. In order to assess the role of antibiotics in the environment on the spread of resistance factors, the impact of subinhibitory concentrations of antibiotics in sewage on gene transfer was investigated using conjugative gentamicin resistance (aacA-aphD) plasmids of Staphylococcus aureus. Furthermore, the concentration of antibiotics in hospital sewage was measured by high-performance liquid chromatography (HPLC)-electrospray tandem mass spectrometry. Several antibiotics were found to be present in sewage, e.g. ciprofloxacin up to 0.051 mgl(-1) and erythromycin up to 0.027 mgl(-1). Resistance plasmid transfer occurred both on solidified (dewatered) sewage and in liquid sewage in a bioreactor with a frequency of 1.1x10(-5)-5.0x10(-8). However, low-level concentrations of antibiotics measured in sewage are below concentrations that can increase plasmid transfer frequencies of gentamicin resistance plasmids of staphylococci.

Analytical method for the determination of the aminoglycoside gentamicin in hospital wastewater via liquid chromatography-electrospray-tandem mass spectrometry.

A method for the determination of gentamicin residues in hospital wastewater has been developed using kanamycin as a surrogate standard. The method consists of solid-phase extraction (SPE) and detection by ion-pair chromatography with electrospray tandem mass spectrometry (LC-ES-tandem MS). The SPE was performed on a weak cation exchanger. Filtration should be avoided in the sample preparation, otherwise a significant loss of gentamicin occurs. Chromatographic separation on a C18-column was achieved using a ternary eluent containing methanol, water and 1(-1) heptafluorobutyric acid solution. Mean relative recoveries of the analytes in hospital wastewater varied between 107 and 111%. The limit of quantification (LOQ) was 0.20 microg l(-1) in hospital wastewater. Gentamicin was found in native hospital wastewater in a concentration range between 0.4 and 7.6 microg l(-1).

Determination of acidic pharmaceuticals, antibiotics and ivermectin in river sediment using liquid chromatography-tandem mass spectrometry.

Analytical methods have been developed for the determination of eight acidic pharmaceuticals and two metabolites, seven antibiotics and the parasiticide ivermectin in a selected river sediment. The sediments were solvent extracted with ultrasonic assistance. A solid phase extraction (SPE) clean-up step was performed thereafter. The acidic compounds clofibric acid, diclofenac, fenoprofen, gemfibrozil, ibuprofen, 2-hydroxy-ibuprofen, indomethacin, ketoprofen, naproxen and the parasiticide ivermectin were measured in the negative mode by LC-APCI-tandem MS, whereas the antibiotics clarithromycin, erythromycin, roxithromycin, sulfadiazine, sulfamethazine, sulfamethoxazole and trimethoprim were detected in the positive mode by LC-ESI-tandem MS. Bezafibrate could not be determined in the sediment using the method developed. The limit of quantification (LOQ) ranged from 0.4 to 8 ng g(-1) for the acidic pharmaceuticals, sulfadiazine and ivermectin and was 20 ng g(-1) for the other antibiotics.