Tuning down the environmental interests of organoclays for emerging pollutants: Pharmaceuticals in presence of electrolytes.

The impact of electrolytes on the adsorption of emerging pollutants: pharmaceuticals onto layered materials: a raw clay mineral and its nonionic and cationic organoclay derivatives was studied. The selected pharmaceuticals: amoxicillin, norfloxacin, sulfamethoxazole, metoprolol, carbamazepine, and trimethoprim show different electric charges: zwitterionic, anionic, cationic and neutral and hydrophobic character (different LogP). Without any salts, the set of complementary data obtained by UV and infrared spectroscopies, X-ray diffraction points out the importance of the electric charge which represents a key parameter in both the spontaneity and feasibility of the adsorption. In contrast, the hydrophobicity of the analytes plays a minor role but determines the magnitude of the adsorbed amount of pharmaceuticals onto organoclays. With a dual hydrophilic and hydrophobic behavior, nonionic organoclay appears to be the most polyvalent material for the removal of the pharmaceuticals. In the presence of electrolytes (NaCl at a concentration of 1 × 10-2 mol L-1), both nonionic and cationic organoclays show a decrease of their efficiencies, whereas the adsorption is particularly enhanced for Na-Mt except for the cationic species (trimethoprim and metoprolol). Thus, in realistic experimental conditions close to those of natural effluents, raw clay mineral appears as the most appropriate sorbent for the studied pharmaceuticals while it raises the question of the usefulness of organoclays in water remediation strategy.

Determination of sulfadiazine, trimethoprim, and N(4) -acetyl-sulfadiazine in fish muscle plus skin by Liquid Chromatography-Mass Spectrometry. Withdrawal-time calculation after in-feed administration in gilthead sea bream (Sparus aurata L.) fed two different diets.

This study presents a depletion study for sulfadiazine and trimethoprim in muscle plus skin of gilthead sea bream (Sparus aurata L.). N(4) -acetyl-sulfadiazine, the main metabolite of sulfadiazine (SDZ), was also examined. The fish were held in seawater at a temperature of 24-26 °C. SDZ and trimethoprim (TMP) were administered orally with medicated feed for five consecutive days at daily doses of 25 mg SDZ and 5 mg TMP per kg of fish body weight per day. Two different diets, fish oil- and plant oil-based diets, were investigated. Ten fish were sampled at each of the days 1, 3, 5, 6, 8, 9, 10, and 12 after the start of veterinary medicine administration. However for the calculation of the withdrawal periods, sampling day 1 was set as 24 h after the last dose of the treatment. Fish samples were analyzed for SDZ, TMP, and acetyl-sulfadiazine (AcSDZ) residues by liquid chromatography-mass spectrometry. SDZ and TMP concentrations declined rapidly from muscle plus skin. Considering a maximum residue limit of 100 µg/kg for the total of sulfonamides and 50 µg/kg for TMP residues in fish muscle plus skin, the withdrawal periods of the premix trimethoprim-sulfadiazine 50% were calculated as 5 and 6 days, at 24-26 °C, in fish oil (FO) and plant oil (PO) groups, respectively. The investigation of this work is important to protect consumers by controlling the undesirable residues in fish.

Identification and quantitation of the ingredients in a counterfeit Vietnamese herbal medicine against rheumatic diseases.

Counterfeit and/or illegally manufactured drugs and herbal medicines are becoming an increasing problem throughout the world. Internet sales simplify distribution and payment of these falsified drugs. Here we report on a Vietnamese herbal medicine, which was advertised for treatment of rheumatic disease from a religious Vietnamese healer. By means of NMR and LC/MS we found 863mg acetaminophen, 262mg sulfamethoxazole, 42mg indomethacin and less than 1% trimethoprim in a sachet of 2.617g powder content, in addition to some cinnamon bark and phosphate.

Evaluating the vulnerability of surface waters to antibiotic contamination from varying wastewater treatment plant discharges.

Effluents from three wastewater treatment plants with varying wastewater treatment technologies and design were analyzed for six antibiotics and caffeine on three sampling occasions. Sulfamethoxazole, trimethoprim, ciprofloxacin, tetracycline, and clindamycin were detected in the effluents at concentrations ranging from 0.090 to 6.0 microg/L. Caffeine was detected in all effluents at concentrations ranging from 0.19 to 9.9 microg/L. These findings indicate that several conventional wastewater management practices are not effective in the complete removal of antibiotics, and their discharges have a large potential to affect the aquatic environment. To evaluate the persistence of antibiotics coming from the wastewater discharges on the surrounding surface waters, samples were collected from the receiving streams at 10-, 20- and 100-m intervals. Ciprofloxacin, sulfamethoxazole, and clindamycin (0.043 to 0.076 microg/L) were found as far as 100 m from the discharge point, which indicates the persistence of these drugs in surface waters.

Hair analysis as a novel investigative tool for the detection of historical drug use/misuse in the horse: a pilot study.

REASONS FOR PERFORMING STUDY: Analysis of human hair for drug residues is being used increasingly as a diagnostic tool in the investigation of drug use and abuse. Hair analysis is complementary to urine/blood testing in that it can provide an extensive historical record of drug use, is noninvasive, impersonal and can facilitate retesting. However, the technique has not been studied in horses. HYPOTHESIS: That the systemic administration of drugs in horses could be identified by the detection of drug residues in hair. OBJECTIVE: To evaluate hair analysis as a potential retrospective diagnostic test for drug administration in horses by studying the deposition of systemically administered drugs in tail hair. METHODS: Tail hairs (n = 40-50) from 4 horses with known drug histories were washed, chopped into 3-5 mm fragments and extracted overnight, in 0.1 mol/l hydrochloric acid, prior to solid-phase extraction and analysis by high-performance liquid chromatography. Horse 1, a 3-year-old Thoroughbred colt (gastric ulcer), was treated for 14 days with omeprazole; Horse 2, a 3-year-old Thoroughbred colt (anaerobic infection), was treated for 5 days with metronidazole; Horse 3, an 8-year-old Thoroughbred gelding (sinusitis), was treated for 10 days with trimethoprim/sulphadiazine; and Horse 4, a 3-year-old Thoroughbred colt (respiratory infection), was treated for 5 days with procaine benzylpenicillin. RESULTS: Omeprazole was not detected in tail hair. Metronidazole was detected in tail hair at a concentration of 0.57 ng/mg, trimethoprim and sulphadiazine at concentrations of 9.14 and 2.26 ng/mg, respectively, and procaine at a concentration of 1.66 ng/mg. CONCLUSIONS: The data presented suggest that hair analysis may become a useable technique for the retrospective detection of drug administration in horses. POTENTIAL RELEVANCE: This technique could ultimately be used as part of a prepurchase veterinary examination to identify misuse of anti-inflammatory and sedative drugs, in an in-training testing programme to identify use of anabolic agents, or to provide evidence to support post race blood or urine test results. Clearly, more extensive research will be required to evaluate the effectiveness of the technique over a much broader range of drugs.

Treatment of experimental staphylococcal osteomyelitis with rifampin and trimethoprim, alone and in combination.

Rifampin and trimethoprim were used alone and in combination in the treatment of chronic osteomyelitis due to Staphylococcus aureus in rabbits. Rifampicin levels in infected bone were well above the minimum inhibitory concentration of the infecting strain of S. aureus for at least 4 h after injection. In contrast, trimethoprim levels in diseased bone were below the minimum inhibitory concentration as early as 1 h after injection. Trimethoprim or rifampin, administered alone for 14 days, were ineffective in sterilizing infected rabbit bones. The combination of rifampin plus trimethoprim was significantly more effective (P less than 0.005) than either agents given alone for a comparable duration of time. Staphylococci isolated from the bones of rabbits treated with rifampin alone or rifampin plus trimethoprim were uniformly resistant to rifampin, but retained their susceptibility to trimethoprim.