Concentrations Of Trimethoprim Research Articles

Formulation, in vitro characterization and optimization of taste-masked orally disintegrating co-trimoxazole tablet by direct compression.

Orally disintegrating tablet (ODT) is a dosage form that overcomes the problem of swallowing which is prevalent in about 35% of the general population. Co-trimoxazole (CTX) is given for patients with HIV for the prophylaxis of opportunistic infection (OI), commonly for pneumocystis carinii pneumonia. It was reported that CTX was associated with a 25-46% reduction in mortality among individuals infected with HIV in sub-Saharan Africa. Esophageal candidiasis which usually comes along with HIV/AIDS is one of AIDS defining illness affecting up to 1 in 5 of people with AIDS. This opportunistic illness is manifested by painful or difficulty of swallowing. In this respect, CTX ODT offer the advantages of both liquid dosage forms in terms of easy swallowing thereby improve patient compliance and solid dosage forms in terms of dose uniformity, stability, lower production, and transportation costs. The objective of this study was to formulate, characterize and optimize CTX ODT which could overcome swallowing problem and improve patient compliance. Co-trimoxazole ODTs were prepared by direct compression technique using a semi synthetic super disintegrant (crospovidone) along with other excipients. Two taste masking techniques were employed, addition of sweetening agent, and solid dispersion by using a pH sensitive polymer, Eudragit E-100 at different ratios (1:1, 1:2 and 1:3). Taste masking was determined by comparing taste threshold value and in vitro drug release. Preliminary study was used to investigate the effect of crospovidone, compression force (CF) and Hydroxypropyl cellulose (HPC) on disintegration time, friability and wetting time (WT). Factorial design was used as it enables simultaneous evaluation of formulation variables and their interaction effect. From the preliminary study, the factors that were found significant were further optimized using central composite design. Design-Expert 8.0.7.1 software was employed to carry out the experimental design. The bitterness threshold concentration of Trimethoprim was found to be 150 μg/ml and the in vitro drug release of the three batches of drug to polymer ratio (F1:1, 1:2 and 1:3) was 2.80±0.05, 2.77±0.00 and 2.63±0.00 respectively. From the optimization study, the optimal concentration for the superdisintegrant was 8.60% w/w and a CF of 11.25 KN which gave a rapid disintegration and WT of 13.79 and 23.19 seconds respectively and a friability of 0.666%. In this study, co-trimoxazole ODT was formulated successfully. Central composite design was effectively used to model and optimize friability, DT and WT. The method was found effective for estimating the effect of independent variables on the dependent variables by using polynomial equation and surface plots. Optimization of the response variables was possible by using both numerical and graphical optimization and the predicted optimal conditions were confirmed experimentally and were found to be in good agreement within 5% of the predicted responses. The results of the study showed that CTX ODT had significantly rapid disintegration, less than 1% friability and enhanced dissolution profiles. The successful formulation of CTX ODT can solve difficulty of swallowing of conventional tablets for some group of patients which are unable to swallow solid oral dosage form.

Emerging contaminants detected in aquaculture sites in Java, Indonesia

Pharmaceuticals of emerging concern (acetaminophen (ACM), trimethoprim (TMP), oxytetracycline (OTC), and sulfamethoxazole (SMX)) were detected in water samples from aquaculture environments and nonaquaculture sites in four regions located on the northern coast of Central Java. ACM was the most prevalent pharmaceutical, with a mean concentration ranging from not detected (n.d.) to 5.5 ± 1.9 ngL−1 (Brebes). Among the target antibiotics (TMP, OTC, SMX), OTC was the most ubiquitous, with a mean concentration varying from n.d. to 8.0 ± 3.3 ngL−1. Correlation analysis demonstrated that there was a significant correlation between TMP and SMX concentrations. Based on ecological risk assessment evaluation, the use of OTC requires serious consideration, as it presented high health risks to algae, while ACM, TMP, and SMX posed an insignificant to moderate risk to algae, invertebrates, and fish. The findings obtained from this study highlight OTC as an emerging contaminant of prominent concern. More attention needs to be given to managing and planning for the sustainable management of shrimp farms, particularly in the northern part of Central Java.

Degradation of trimethoprim in aqueous by persulfate activated with nanosecond pulsed gas-liquid discharge plasma

The persulfate activation by nanosecond pulsed gas-liquid discharge (NPG-LD) is employed to degrade the trimethoprim (TMP) in water. The results show that persulfate addition enhances the degradation of TMP by NPG-LD through an obvious synergetic effect. With treatment time of 50 min, the high removal efficiency and energy yield reach 94.6% and 0.57 gkWh−1 in air NPG-LD with the addition of persulfate, respectively, which is 13.5% and 0.09 gkWh−1 higher than that in solo air NPG-LD, respectively. Correspondingly, the calculated synergetic factor achieves 1.62, indicating the synergetic effect is established. The activation mechanism of persulfate by NPG-LD is analyzed by the measurement of reactive species and the effects of radical scavenger addition on TMP removal. It is found that the synergetic effect between NPG-LD and persulfate is attributed to the increased production of OH, H2O2, and ▪. Besides, the TMP degradation by NPG-LD and persulfate synergetic system is influenced by discharge working gas, pulse voltage, addition dosage of persulfate, initial TMP concentration, and initial pH value. Subsequently, the degradation pathway of TMP is analyzed using LC-MS/MS.

Dissipation of sulfamethoxazole and trimethoprim during temporary storage of biosolids: A microcosm study

Little is known about the dissipation rate of microcontaminants in biosolids during storage and stabilization in stockpiles (unsaturated) or storage lagoons/tanks (saturated). The objective of this study was to characterize the dissipation in biosolids of two antibiotics, sulfamethoxazole (SMX) and trimethoprim (TMP), in microcosms under saturated and unsaturated conditions that simulate biosolids that are stockpiled on land or deposited in lagoons/tanks, respectively. The laboratory experiment was conducted at 22 °C using biosolids spiked at an initial nominal concentration of 10 mg kg−1 for both antibiotics. Biosolids were sampled in triplicate at seven sampling times over a 42-d period. Concentrations of SMX and TMP in extracts prepared from biosolids were quantified using liquid chromatography with tandem mass spectrometry. Dissipation data fitted to a first-order kinetic model indicated that the time to 50% dissipation (DT50) for SMX was significantly shorter in the unsaturated microcosms (2.8 d) than the saturated microcosms (4.4 d), while the DT50 for TMP was significantly shorter in microcosms under saturated conditions (10 d) relative to unsaturated conditions (116 d). These results indicate that the reducing conditions that develop in biosolids deposited in lagoons or placed in storage tanks might be effective for enhancing the microbial degradation of antibiotics that are otherwise persistent under aerobic conditions (i.e., TMP), while also being effective for removing other antibiotics including those that dissipate relatively readily under aerobic conditions (i.e., SMX).

A rapid screening method for the detection of specialised metabolites from bacteria: Induction and suppression of metabolites from Burkholderia species

Screening microbial cultures for specialised metabolites is essential for the discovery of new biologically active compounds. A novel, cost-effective and rapid screening method is described for extracting specialised metabolites from bacteria grown on agar plates, coupled with HPLC for basic identification of known and potentially novel metabolites. The method allows the screening of culture collections to identify optimal production strains and metabolite induction conditions. The protocol was optimised on two Burkholderia species known to produce the antibiotics, enacyloxin IIa (B. ambifaria) and gladiolin (B. gladioli), respectively; it was then applied to strains of each species to identify high antibiotic producers. B. ambifaria AMMD and B. gladioli BCC0238 produced the highest concentrations of the respective antibiotic under the conditions tested. To induce expression of silent biosynthetic gene clusters, the addition of low concentrations of antibiotics to growth media was evaluated as known elicitors of Burkholderia specialised metabolites. Subinhibitory concentrations of trimethoprim and other clinically therapeutic antibiotics were evaluated and screened against a panel of B. gladioli and B. ambifaria. To enhance rapid strain screening with more antibiotic elicitors, antimicrobial susceptibility testing discs were included within the induction medium. Low concentrations of trimethoprim suppressed the production of specialised metabolites in B. gladioli, including the toxins, toxoflavin and bongkrekic acid. However, the addition of trimethoprim significantly improved enacylocin IIa concentrations in B. ambifaria AMMD. Rifampicin and ceftazidime significantly improved the yield of gladiolin and caryoynencin by B. gladioli BCC0238, respectively, and cepacin increased 2-fold with tobramycin in B. ambifaria BCC0191. Potentially novel metabolites were also induced by subinhibitory concentrations of tobramycin and chloramphenicol in B. ambifaria. In contrast to previous findings that low concentrations of antibiotic elicit Burkholderia metabolite production, we found they acted as both inducers or suppressors dependent on the metabolite and the strains producing them. In conclusion, the screening protocol enabled rapid characterization of Burkholderia metabolites, the identification of suitable producer strains, potentially novel natural products and an understanding of metabolite regulation in the presence of inducing or suppressing conditions.

Regional Differences in Penetration of the Protein Stabilizer Trimethoprim (TMP) in the Rat Central Nervous System.

Regulating gene expression at the protein level is becoming increasingly important for answering basic questions in neurobiology. Several techniques using destabilizing domains (DD) on transgenes, which can be activated or deactivated by specific drugs, have been developed to achieve this goal. A DD from bacterial dihydrofolate reductase bound and stabilized by trimethoprim (TMP) represents such a tool. To control transgenic protein levels in the brain, the DD-regulating drugs need to have sufficient penetration into the central nervous system (CNS). Yet, very limited information is available on TMP pharmacokinetics in the CNS following systemic injection. Here, we performed a pharmacokinetic study on the penetration of TMP into different CNS compartments in the rat. We used mass spectrometry to measure TMP concentrations in serum, cerebrospinal fluid (CSF) and tissue samples of different CNS regions upon intraperitoneal TMP injection. We show that TMP quickly (within 10 min) penetrates from serum to CSF through the blood-CSF barrier. TMP also shows quick penetration into brain tissue but concentrations were an order of magnitude lower compared to serum or CSF. TMP concentration in spinal cord was lower than in any other analyzed CNS area. Nevertheless, effective levels of TMP to stabilize DDs can be reached in the CNS with half-lives around 2 h. These data show that TMP has good and fast penetration properties into the CNS and is therefore a valuable ligand for precisely controlling protein expression in the CNS in rodents.

Selective concentrations for trimethoprim resistance in aquatic environments

Antibiotic resistance presents a serious and still growing threat to human health. Environmental exposure levels required to select for resistance are unknown for most antibiotics. Here, we evaluated different experimental approaches and ways to interpret effect measures, in order to identify what concentration of trimethoprim that are likely to select for resistance in aquatic environments. When grown in complex biofilms, selection for resistant E. coli increased at 100 µg/L, whereas there was only a non-significant trend with regards to changes in taxonomic composition within the tested range (0–100 µg/L). Planktonic co-culturing of 149 different E. coli strains isolated from sewage again confirmed selection at 100 µg/L. Finally, pairwise competition experiments were performed with engineered E. coli strains carrying different trimethoprim resistance genes (dfr) and their sensitive counterparts. While strains with introduced resistance genes grew slower than the sensitive ones at 0 and 10 µg/L, a significant reduction in cost was found already at 10 µg/L. Defining lowest effect concentrations by comparing proportion of resistant strains to sensitive ones at the same time point, rather than to their initial ratios, will reflect the advantage a resistance factor can bring, while ignoring exposure-independent fitness costs. As costs are likely to be highly dependent on the specific environmental and genetic contexts, the former approach might be more suitable as a basis for defining exposure limits with the intention to prevent selection for resistance. Based on the present and other studies, we propose that 1 µg/L would be a reasonably protective exposure limit for trimethoprim in aquatic environments.

Sex-related differences in disposition of sulfamethoxazole, N-acetyl-sulfamethoxazole and trimethoprim in yellow catfish (Pelteobagrus fulvidraco) following a single oral administration

The aim of this present study was to explore the sex-related differences in disposition regularities of sulfamethoxazole (SMZ), N-acetyl-sulfamethoxazole (N-ac-SMZ) and trimethoprim (TMP) in male and female yellow catfish. Concentrations of target compounds were determined using a reliable HPLC-MS/MS approach, which was validated according to the guidelines defined by FDA. The results showed that there are significant sex-associated differences in SMZ concentrations of muscle with skin and liver, in N-ac-SMZ levels of muscle with skin and kidney, and in TMP concentrations of muscle with skin, liver and kidney. Whereas, no significant sex differences were also observed in SMZ, N-ac-SMZ and TMP levels of plasma, in SMZ concentrations of kidney and in N-ac-SMZ concentrations of liver. Longer residue time of N-ac-SMZ than SMZ was observed in male and female yellow catfish. Withdrawal time (WT) of SMZ (N-ac-SMZ as the marker residue) calculated by the WT 1.4 software, was 11 days (male) and 9 days (female), respectively. By contrast, WT of SMZ (SMZ as the marker residue) was 9 days (male) and 7 days (female), respectively. These results could serve as reference data for establishing disparate use regimen and drug withdrawal time of SMZ and TMP in male and female yellow catfish.

Activation of persulfate by biochar from spent malt rootlets for the degradation of trimethoprim in the presence of inorganic ions

AbstractBACKGROUNDAntibiotics such as trimethoprim (TMP) are used in large quantities and recent studies show that TMP is not eliminated completely in wastewater from municipal treatment plants. Advanced oxidation processes (AOPs), especially sulfate radical‐based AOPs, are highly reactive in the presence of a catalyst. Biochar, a green and low‐cost carbon material, is an excellent catalyst to degrade persistent pollutants. In this work, the degradation of TMP is studied using biochar from spent malt rootlets.RESULTSThe biochar has a specific surface area of 62 m2 g–1, point of zero charge 6.8, contains aromatics and is rich in –OH surface groups. The effect of sodium persulfate (SPS) (100–500 mg L–1), TMP (150–500 μg L–1), biochar (BC) concentration (45–180 mg L–1), solution pH (4–9) and water quality on degradation was investigated. The degradation rate increased with increasing SPS and BC concentration, decreasing TMP concentration and water matrix complexity, but remained insensitive to pH changes. Seven transformation products were identified and quantified, including hydroxylated and oxidized keto derivatives, and reaction pathways/mechanisms are proposed. The BC activation was coupled with low‐frequency ultrasound (20 kHz), which plays a synergistic role in degradation, but not when coupled with simulated solar irradiation.CONCLUSIONThe occurrence of various ions in bottle water (BW) impact negatively TMP degradation and so does the existence of organic matter in treated wastewaters. The studied reaction seems to be a surface process where the biochar serves as a platform to generate sulfate and –OH radicals, as well as an electron transfer mediator. © 2020 Society of Chemical Industry

Application of UV/vis spectrophotometry based on using least squares support vector machine and continuous wavelet transform methods for the simultaneous analysis of antibiotics drugs in tablet formulation: Comparison with HPLC method

In this study, chemotremic methods with the spectrophotometric method was used for simultaneous determination of Trimethoprim (TMP) and Sulfamethoxazole (SMZ) in Co-trimoxazole tablet without the need separation steps. The proposed methods included the least squares support vector machine (LS-SVM) and continuous wavelet transform (CWT). Modeling of suggested methods was tested by synthetic mixtures containing different concentrations of TMP and SMZ. Root mean square error (RMSE) of the LS-SVM model was 0.471 and 0.147 for TMP and SMZ, respectively. On the other hand, in the CWT method, different families of wavelets were studied. The Daubechies (Db2) and Biortogonal (rbio2.2) wavelet families were selected to analyze TMP and SMZ, respectively. In this method, the mean recovery values related to the synthetic mixtures were 99.69 % and 98.15 % for TMP and SMZ, respectively. The obtained results from analyzing the real sample (Co-trimoxazole) by the proposed methods were compared to the high-performance liquid chromatography (HPLC) as a reference method. One-way ANOVA test at the 95 % confidence level was applied to the results. The data showed that there were no significant differences between the proposed and the reference methods.

Application of Rank Annihilation Factor Analysis for Antibacterial Drugs Determination by Means of pH Gradual Change-UV Spectral Data.

The main objective of this study was to develop a simple and efficient spectrophotometric technique combined with chemometrics for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in drug formulations. Specifically, we sought: (i) to evaluate the potential use of rank annihilation factor analysis (RAFA) to pH gradual change spectrophotometric data in order to provide sufficient accuracy and model robustness; and (ii) to determine SMX and TMP concentration in drug formulations without tedious pre-treatments such as derivatization or extraction techniques which are time-consuming and require hazardous solvents. In the proposed method, the spectra of the sample solutions at different pH values were recorded and the pH-spectra bilinear data matrix was generated. On these data, RAFA was then applied to estimate the concentrations of SMX and TMP in synthetic and real samples. Applying RAFA showed that the two drugs could be determined simultaneously with concentration ratios of SMX to TMP varying from 1:30 to 30:1 in the mixed samples (concentration range is 1–30 µg mL−1 for both components). The limits of detection were 0.25 and 0.38 µg mL−1 for SMX and TMP, respectively. The proposed method was successfully applied to the simultaneous determination of SMX and TMP in some synthetic, pharmaceutical formulation and biological fluid samples. In addition, the means of the estimated RSD (%) were 1.71 and 2.18 for SMX and TMP, respectively, in synthetic mixtures. The accuracy of the proposed method was confirmed by spiked recovery test on biological samples with satisfactory results (90.50–109.80%).

Spectrometric determination of trimethoprim and sulfamethoxazole in tablets by automated sequential injection technique

An automated sequential injection analysis with spectrometric detection for the determination of trimethoprim and sulfamethoxazole in tablets is proposed. The concentration of sulfamethoxazole is determined by monitoring the absorbance at 540 nm due to the intensively colored complex formed by derivatization reaction of sulfamethoxazole with nitrite and N-(1-naphthyl)ethylenediamine in acidic media. With knowledge of the sulfamethoxazole concentration, the trimethoprim concentration can be calculated from the absorption of the sample solution at 264 nm, where both analytes absorb, and the additivity of individual absorbances according to Beer-Lambert law can be used. The developed method has a linear dynamic range of 0.03–5.0 mg dm−3 and a detection limit of 0.03 mg dm−3 for trimethoprim and a linear dynamic range of 0.1–10.0 mg dm−3 and a detection limit of 0.01 mg dm−3 for sulfamethoxazole. The sampling frequency of the method is 24 h−1. The method was successfully applied on pharmaceutical dosage form of tablets, as the results of the determination are in a good agreement with the official pharmacopoeial method (HPLC). The developed sequential injection analysis is simpler, cheaper, and faster than already published methods and pharmacopoeial assay. So it appears to be suitable for quality control in the pharmaceutical industry.

MIL-53(Al)/ZnO coated plates with high photocatalytic activity for extended degradation of trimethoprim via novel photocatalytic reactor

Metal organic frameworks (MOFs) have been recently utilized in many environmental applications including photocatalysis. Herein, we report a developed photocatalytic reactor to exploit a novel composite of MIL-53(Al)/ZnO for the degradation of trimethoprim. Zn-free MIL53(Al) was synthesized and employed as a reactive template to obtain MIL-53(Al)/ZnO nanoparticles by hydrothermal method. The analyses by XRD, Raman spectroscopy, XPS, TEM, and EDX affirmed the growth of the desired composite. MIL-53(Al)/ZnO was coated on glass plates using polysiloxane; thereafter, the plates were placed in the photocatalytic reactor. The optimization of the operating parameters was performed by the response surface methodology (RSM) coupled with a central composite design (CCD), yielding optimum pH, flow rate, and initial trimethoprim concentration of 8.4, 5.3 mL/min, and 6.9 mg/L, respectively. The extended operation of the MIL-53(Al)/ZnO plates for five continuous cycles corroborated the stable photocatalytic activity and the prospect of effective reuse. The contributions of different reactive oxidant species (ROS) were elucidated by employing different radical scavengers. Furthermore, The degradation pathway was proposed via the identification of transformation products by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Our present findings emphasize on the merits of employing the photocatalysts in a retained form, which can be an avenue for practical application of photocatalysis.

Sonochemical degradation of trimethoprim in water matrices: Effect of operating conditions, identification of transformation products and toxicity assessment.

The sonochemical degradation of trimethoprim (TMP), a widely used antibiotic, in various water matrices was investigated. The effect of several parameters, such as initial TMP concentration (0.5-3mg/L), actual power density (20-60W/L), initial solution pH (3-10), inorganic ions, humic acid and water matrix on degradation kinetics was examined. The pseudo-first order degradation rate of TMP was found to increase with increasing power density and decreasing pH, water complexity (ultrapure water>bottled water>secondary wastewater) and initial TMP concentration. TMP degradation is accompanied by the formation of several transformation products (TPs) as evidenced by LC-QToF-MS analysis. Nine such TPs were successfully identified and their time-trend profiles during degradation were followed. An in silico toxicity evaluation was performed showing that several TPs could potentially be more toxic than the parent compound towards Daphnia magna, Pimephales promelas and Pseudokirchneriella subcapitata.

Occurrence of antibiotics and risk of antibiotic resistance evolution in selected Kenyan wastewaters, surface waters and sediments

Active pharmaceutical ingredients, especially antibiotics, are micropollutants whose continuous flow into hydrological cycles has the potential to mediate antibiotic resistance in the environment and cause toxicity to sensitive organisms. Here, we investigated the levels of selected antibiotics in four wastewater treatment plants and the receiving water bodies. The measured environmental concentrations were compared with the proposed compound-specific predicted no-effect concentration for resistance selection values. The concentration of doxycycline, amoxicillin, sulfamethoxazole, trimethoprim, ciprofloxacin and norfloxacin within the influents, effluents, surface waters and river sediments ranged between 0.2 and 49.3 μgL−1, 0.1 to 21.4 μgL−1; ˂ 0.1 and 56.6 μgL−1; and 1.8 and 47.4 μgkg−1, respectively. Compared to the effluent concentrations, the surface waters upstream and downstream one of the four studied treatment plants showed two to five times higher concentrations of ciprofloxacin, norfloxacin and sulfamethoxazole. The risk quotient for bacterial resistance selection in effluent and surface water ranged between ˂0.1 and 53, indicating a medium to high risk of antibiotic resistance developing within the study areas. Therefore, risk mitigation and prevention strategies are a matter of priority in the affected areas.

Articles of Significant Interest in This Issue

Antimicrobial resistance is mediated by the acquisition of mutations. However, mutations can produce pleiotropic phenotypes. Matange (e00561-19) investigates how antibiotic concentration and genetic background together impact drug tolerance and the potential to evolve resistance. The author demonstrates that loss of Lon protease, a bacterial master regulator, has opposite effects on the survival of Escherichia coli at low and high trimethoprim concentrations. Loss of Lon also expands the mutant repertoire that confers trimethoprim resistance to dihydrofolate reductase (DHFR), the target of trimethoprim in E. coli. This study illuminates complex ways in which drug concentration and genetic background influence the phenotypes and evolution of drug-resistant bacteria.

Occurrence and human health risk assessment of pharmaceuticals and personal care products in real agricultural systems with long-term reclaimed wastewater irrigation in Beijing, China.

Reclaimed wastewater (RW) is increasingly used to irrigate agricultural land and to alleviate agricultural water shortages worldwide. This usage has resulted in concerns about soil contamination by pharmaceuticals and personal care products (PPCPs) and the human health risks associated with dietary crop intake. In this study, we systematically analysed the occurrence and accumulation of 11 PPCPs and one active metabolite in soils and various crops (cucumber, eggplant, long bean and wheat) from realistic RW irrigation fields with different irrigation histories (20, 30 and 40 years) in Beijing and evaluated the human health risks associated with the consumption of these crops. The 11 PPCPs and one active metabolite were detected at concentrations ranging from 0.67 to 22.92ngL-1 in RW, 0.029-28.13μgkg-1 in irrigated soil, and <0.01-28.01μgkg-1 in crops. The concentrations of N4-acetyl-sulfamethoxazole and triclosan were higher than those of other PPCPs, with respective concentrations of 14.39-31.44ngL-1 and 15.93-26.23ngL-1 in RW, 10.92-23.29μgkg-1 and 20.22-28.13μgkg-1 in irrigated soil and 17.92-28.01μgkg-1 and 8.92-14.91μgkg-1 in crops. However, the estimated threshold of toxicological concern (TTC) and hazard quotient (HQ) values revealed that the concentrations of N4-acetyl-sulfamethoxazole and triclosan in crops irrigated with RW should be considered a de minimis risk to human health. The concentrations of 11 PPCPs and one active metabolite in soils and crops and the calculated fruit bioconcentration factors (BCFs) did not display obvious increases associated with the duration of RW irrigation in real agricultural systems (P>0.05). The concentrations of the studied PPCPs in the RW used for irrigation followed different patterns from the concentrations detected in the irrigated soils and crops. Although the concentrations of sulfamethoxazole, sulfisoxazole, sulfamethazine and trimethoprim in RW were higher than those of many other studied PPCPs, their respective values in the irrigated soils and crops did not display a similar tendency. The uptake and accumulation of PPCPs varied among the crop species (P<0.05). Although PPCPs were detected in eggplant, long bean and wheat (BCFs: not applicable-1.67, 0.03-1.35 and 0.01-5.01, respectively), PPCPs accumulated at increased levels in cucumber (BCFs 0.03-18.98). The estimated TTC and HQ values showed that the consumption of crops irrigated long-term with RW presents a de minimis risk to human health. However, further studies with more PPCPs and additional crop species need to be conducted, the synergistic effects of chemical mixtures of multiple PPCPs and the toxic effects of PPCP metabolites should be elucidated to obtain more reliable information on the safety of wastewater reuse for irrigation.

Occurrence and fate of pharmaceuticals in effluent and sludge from a wastewater treatment plant in Brazil

ABSTRACT A wide variety of pharmaceuticals are discharged in water courses on a daily basis due to their incomplete removal from effluent in treatment plants. The aim of the current study was to assess the occurrence, fate and removal of pharmaceuticals from effluent and sludge samples collected in the biggest sanitary sewer plant in Southern Brazil. In total, 13 pharmaceuticals were detected in the influent through UHPLC-MS/M – paracetamol and caffeine recorded the highest concentrations, 137.98 and 35.29 µg L−1, respectively. The treated effluent presented 11 compounds. Antibiotics were the class recording the widest diversity; metronidazole showed the lowest concentration (0.023 µg L−1) and sulfamethoxazole presented the highest concentration (1.374 µg L−1) in influent samples. Seven pharmaceuticals were absorbed by the sludge; among them, one finds caffeine, ciprofloxacin and ofloxacin, which were quantified both in the effluent and in the sludge. On the other hand, doxycycline, fenbendazole, norfloxacin and tetracycline were only detected in sludge samples – their concentrations ranged from 0.026 to 5.034 mg kg−1. Clindamycin, oxytetracycline, sulfathiazole and trimethoprim concentrations increased throughout the treatment. There were high paracetamol and caffeine removal rates (>97%), and it may have happened due to degradation, photodegradation or chemical reaction. Ciprofloxacin and ofloxacin removal rate exceeded 83% mainly due to their sorption by sludge. Finally, the mass balance analysis highlighted high pharmaceutical loads (511.466 g d−1) discharged into recipient waterbodies. This outcome demands broadening the removal of these pharmaceuticals from sewage.

Photocatalytic degradation of trimethoprim using S-TiO2 and Ru/WO3/ZrO2 immobilized on reusable fixed plates

In this study, photocatalytic degradation of trimethoprim by synthesized S-TiO2 and Ru/WO3/ZrO2 catalysts was investigated. Both photocatalysts have been immobilized on circular aluminum plates by polysiloxane to investigate their reusability performance. The morphology and structure of the catalysts were studied by high-resolution transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The photocatalytic experiments were carried out using suspended and attached catalysts using a metal halide lamp as a light source. The degradation efficiencies of trimethoprim were 100% and 98.2% at catalyst dose of 0.5 g/L, pH of 7.0 and irradiation time of 240 min using suspended Ru/WO3/ZrO2 and S-TiO2, respectively. After immobilization of the catalysts on the aluminum plates, the removal efficiencies in five repetitive cycles were 98%, 96.9%, 96.8%, 93.2% and 83.4% using Ru/WO3/ZrO2, while they were 88.6%, 86%, 84%, 78% and 75.9% in case of S-TiO2. The irradiation time of each cycle was 240 min, and the initial trimethoprim concentration was 10 mg/L. The degradation rates of trimethoprim were estimated in the case of suspended and immobilized S-TiO2 and Ru/WO3/ZrO2. The radical trapping experiments using various scavengers revealed that superoxide radicals, holes and hydroxyl radicals all participated in the photo-degradation process. Furthermore, the transformation products generated during the trimethoprim oxidation process were detected by liquid chromatography/mass spectroscopy to identify the possible degradation pathways.

Assessment of the distribution and concentration of residual antibiotics in chicken meat and liver samples collected in Tehran by Liquid Chromatography and Tandem Mass Spectrometry

Background: Antibiotics are extensively used as therapeutic, prophylactic and growth promoting agents in the poultry industry. However, their widespread use resulted in the presence of residuals in poultry meat and offals potentially leading to public health hazards. The present research was done to assess the distribution and concentration of residual antibiotics in chicken meat and liver samples. Methods: Ninety chicken meat and liver samples were collected and transferred to laboratory. Presence and concentration of residual tetracyclines, sulfonamides and trimethoprim were assessed using the Liquid Chromatography -Tandem Mass Spectrometry technique. Results: There were no detectable concentrations of tetracyclines in all studied samples. Twenty-eight out of 90 (31.11%) raw meat and 31 out of 90 (34.44%) liver samples were positive for residual sulfonamides. Prevalence of positive meat and liver samples for residual sulfachloropyrazine, sulfadimethoxine and trimethoprim antibiotics were 16.66%, 5.55% and 8.88% and also16.66%, 5.55% and 11.11%, respectively. Sulfathiazole residue was only detected in 1.11% of chicken liver samples. Chicken liver samples had the higher concentrations of all detected residual sulfonamides. Sulfachloropyrazine had the highest concentration in raw chicken meat (20.8±1.88 µg/kg) and liver (24.4±1.54 µg/kg) samples, while sulfadimethoxine had the lowest (6.05±0.25 µg/kg and 9.26±0.36 µg/kg, respectively). Conclusion: All detected concentrations of residual sulfonamides were lower than Maximum Residue Limits (MRLs). Presence of residual antibiotics represents a serious public health treat regarding the occurrence of antibiotic resistant bacterial strains. LC MS/MS has been introduced as a sensitive and specific technique for monitoring and surveillance of residual antibiotics in chicken samples.