Synthesis, characterization and biological studies of a cobalt(III) complex of sulfathiazole.

The emergence of old and new antibiotic resistance created in the last decades revealed a substantial medical need for new classes of antimicrobial agents. The antimicrobial activity of sulfa drugs is often enhanced by complexation with metal ions, which is in concordance with the well-known importance of metal ions in biological systems. Besides, sulfonamides and its derivatives constitute an important class of drugs, with several types of pharmacological agents possessing antibacterial, anti-carbonic anhydrase, diuretic, hypoglycemic, antithyroid, antiviral and anticancer activities, among others. The purpose of this work has been the obtainment, characterization and determination of biological properties (antibacterial, antifungal, mutagenicity and phytotoxicity) of a new Co(III)-sulfathiazole complex: Costz, besides of its interaction with bovine serum albumin (BSA). The reaction between sodium sulfathiazole (Nastz) and cobalt(II) chloride in the presence of H2O2 leads to a brown solid, [CoIII(stz)2OH(H2O)3], (Costz). The structure of this compound has been examined by means of elemental analyses, FT-IR, 1H NMR, UV-Visible spectrometric methods and thermal studies. The Co(III) ion, which exhibits a distorted octahedral environment, could coordinate with the N thiazolic atom of sulfathiazolate. The complex quenched partially the native fluorescence of bovine serum albumin (BSA), suggesting a specific interaction with the protein. The Costz complex showed, in vitro, a moderate antifungal activity against Aspergillus fumigatus and A. flavus. As antibacterial, Costz displayed, in vitro, enhanced activity respective to the ligand against Pseudomonas aeruginosa. Costz did not show mutagenic properties with the Ames test. In the Allium cepa test the complex showed cytotoxic properties but not genotoxic ones. These results may be auspicious, however, further biological studies are needed to consider the complex Costz as a possible drug in the future.

Evaluation of sulfathiazole degradation by persulfate in Milli-Q water and in effluent of a sewage treatment plant.

The presence of antibiotics and their metabolites in natural waters has raised some concern among scientists around the world because it can lead to bacterial resistance and other unknown consequences to mankind and wildlife. Persulfate (PS)-driven oxidation is a new technology that has been used successfully to remediate contaminated sites, but its use to treat wastewater, especially sewage treatment plant (STP) effluent, is still scarce. This paper describes the effect of several persulfate activation methods for degrading sulfathiazole (STZ) in Milli-Q water and in STP effluent. Some parameters, such as pH, persulfate concentration, presence of Mn2+, Zn2+, Cu2+, Fe2+, and Fe3+, as well as copper and iron organic complexes, were studied in STZ degradation. Raising the pH from 5 to 9, as well as the persulfate concentration, resulted in increased STZ degradation. Among the transition metals evaluated, only Fe2+ and Cu2+ were able to activate persulfate molecules. Copper was a better activator than iron since its effect lasts longer. Citrate was the best ligand evaluated increasing Fe(II) activation capacity at pH 7. Hydroxylamine addition to Fe(II) on persulfate system extended the Fe(II) effect. The presence of bicarbonate or humic acid did not affect PS-driven degradation of STZ. Finally, the degradation of STZ in STP effluent promoted by PS-driven oxidation (25 °C) was as fast as in Milli-Q water, proving to be successful.

Oxidative degradation of sulfathiazole by Fenton and photo-Fenton reactions.

This article presents experimental results on 47 µmol L(-1) sulfathiazole (STZ) degradation by Fenton and photo-Fenton reactions using multivariate analysis. The optimal experimental conditions for reactions were obtained by Response Surface Methodology (RSM). In the case of the Fenton reactions there were 192 µmol L(-1) ferrous ions (Fe(II)) and 1856 µmol L(-1) hydrogen peroxide (H2O2), as compared with 157 µmol L(-1) (Fe(II)) and 1219 µmol L(-1) (H2O2) for photo-Fenton reactions. Under these conditions, around 90% of STZ degradation were achieved after 8 minutes treatment by Fenton and photo-Fenton reactions, respectively. Moreover, a marked difference was observed in the total organic carbon (TOC) removal after 60-min treatment, achieving 30% and 75% for the Fenton and photo-Fenton reactions, respectively. Acetic, maleic, succinic and oxamic acids could be identified as main Fenton oxidation intermediates. A similar pattern was found in the case of photo-Fenton reaction, including the presence of oxalic acid and ammonia at short periods of irradiation with UV-A. The calculated values of Average Oxidation State (AOS) corroborate the formation of oxidized products from the initial steps of the reaction.

A reliable high-performance liquid chromatography with ultraviolet detection for the determination of sulfonamides in honey.

The sulfonamides are stable chemotherapeutics used against the bacterial disease affecting bees, known as American foulbrood (Bacillus larvae), so their residues could appear in the honey of treated bees. Their presence at a concentration above the limit value is a potential hazard to human health. Brazilian authorities have included in the National regulatory monitoring program, the control of the three most widely used sulfonamides in honey production, i.e., sulfathiazole, sulfamethazine and sulfadimethoxine. A method for the determination of residual sulfonamides in honey, using sulfapyridine as an internal standard has been developed, optimized and validated. Some changes were implemented on current available methodologies for the analysis of sulfonamides in honey in order to adopt such procedures to Brazilian honey samples. Sulfonamides were extracted from honey with dichloromethane after dissolution with 30% sodium chloride, and cleaned up with solid phase extraction on Florisil columns. The eluate was analyzed by high-performance liquid chromatography with ultraviolet detection. The limit of detection was determined at 3 microg kg(-1), 4 microg kg(-1) and 5 microg kg(-1) for sulfathiazole, sulfamethazine and sulfadimethoxine, respectively with average recoveries of 61.0% for sulfathiazole; 94.5% for sulfamethazine and 86.0% for sulfadimethoxine at the 100 microg kg(-1) level. As the final step of validation procedure, the analysts were submitted to a blind spiked sample prepared by the quality assurance officer which results were successfully obtained regarding recovery and deviations.

Serum activity/concentration profiles of a sustained-released formulation of sulphathiazole-trimethoprim (2.5:1) in calves.

Thirty-six two-week-old healthy Holstein-Friesian calves weighing between 52 and 58 kg were divided at random into three groups of 12; group A calves were given a single oral bolus containing 2.5 g sulphathiazole and 1 g trimethoprim in a sustained-release formulation; group B received the same doses of the drugs but the trimethoprim was not in a sustained-release formulation; group C received a bolus containing 2.5 g sulphathiazole and 0.5 g conventional trimethoprim. Blood samples were collected at intervals for two days, the serum was separated and the composite antibacterial activity profiles of the mixture were analysed by an agar-diffusion microbiological method. The mean maximum activities in the serum of the three groups were 23.4 microg/ml in group A, 9.25 microg/ml in group B and 8.01 microg/ml in group C. The mean areas under the curves of the serum activity time curves were 838 microg/ml/hour in group A, 216 microg/ml/hour in group B and 182 microg/ml/hour in group C.

Estudo das biocompatibilidade do sulfatiazol em pó no tecido subcutâneo localmente anestesiado / Study of the biocompatibility of sulfathiazole powder in locally anesthetizhed subcutaneous tissue

O propósito desse estudo foi avaliar a biocompatibilidade do sulfatizol (ST) e sua absorção no tecido subcutâneo localmente anestesiado. Uma loja cirúrgica foi preparada no tórax ventral de 90 ratos Wistar machos para a colocação do ST e como sítios controles. Foram 3 grupos experimentais: grupo 1, ST somente, grupo 2, ST com prévia infiltração de lidocaína a 2 por cento, grupo 3, controle (Sham). A resposta tissular foi avaliada histologicamente aos 2, 10 e 30 dias. Observou-se que ST atua como um corpo estranho que interfere na cicatrização tecidual e que o agente anestésico retardou a absorção e aumento do dano tecidual. Histometricamente o grupo 2 apresentou áreas de reabsorção tecidual mais extensas quando comparado aos grupos 1 e 3 (p<0,05). Os resultados indicaram claramente que a combinação do ST com a solução anestésica local é mais prejudicial para os tecidos moles que o ST sozinho

Isosporíase: atualizaçäo / Isosporiasis: review

Os autores fazem uma atualizaçäo sobre isosporíase humana e abordam os principais aspectos da parasitose: epidemiologia, quadro clínico, diagnóstico laboratorial e terapêutica clínica

Efficacy of trimethoprim-sulfamethoxazole in treatment of acute diarrhea in a Mexican pediatric population.

The efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) and placebo were compared in a randomized double-blind study of 141 Mexican children with acute diarrhea. Patients who met specific entry criteria received TMP-SMX or an identical appearing placebo for 5 days. Stools were examined for bacterial, viral, and parasitic pathogens. Enterotoxigenic Escherichia coli were the most commonly isolated pathogens (22% of total). Patients given TMP-SMX had a significantly shorter time to "last illness stool" than did those given placebo, but no difference in number of unformed stools in 5 days was found between treatment groups. However, TMP-SMX significantly shortened the illness in patients with fever or many fecal leukocytes. When stool cultures positive for any bacterial pathogen or for enterotoxigenic E. coli were analyzed as separate groups, a significantly faster recovery was observed in patients given TMP-SMX. TMP-SMX is efficacious in the treatment of Mexican children with diarrhea and culture-proved bacterial infection or when the clinical signs and symptoms suggest bacterial enteritis.

Increasing resistance to trimethoprim-sulfamethoxazole among isolates of Escherichia coli in developing countries.

Resistance of Escherichia coli to trimethoprim (TMP)-sulfamethoxazole remains at 3%-8% at many medical centers within the United States. In this study a 44% resistance rate was observed among E. coli isolated at a pediatric hospital in Santiago, Chile, and a 40% resistance rate at a general teaching hospital in Bangkok, Thailand. Most isolates were from urinary tract infections and showed high-level resistance (minimal inhibitory concentration of TMP greater than 1,000 micrograms/ml). Nineteen of 35 isolates tested transferred resistance to TMP; most cotransferred resistance to streptomycin and sulfonamides. Dihydrofolate reductase type I was detected by gene probing in 14 of 35 strains. Subsequent investigations in Brazil, Honduras, and Costa Rica revealed that this high rate of resistance was not an isolated phenomenon.

Açäo da anfotericina B e Levamisole em camundongos albinos inoculados com Paracoccidioidomicose Brasiliensis / Study on anphotericin B and levamisole in albino mice inoculated with paracoccidioides brasiliensis

Paracoccidioidomicose experimental, em camundongos albinos de 3-4 semanas de idade. Inoculaçäo de 0,5 ml de suspensäo, contendo 1x10(devada a sexta potência) células/ml de Paracoccidioides brasiliensis e tratamento com anfotericina B (1 mg/Kg) em doses diárias; com levamisole (3 mg/Kg) administrada em intervalos de 15 dias e em séries de uma dose por dia, em três dias consecutivos; e com anfotericina B e levamisole associadas, de maneira a cobrir o período de 50, 80 e 95 dias para necrópsia. Estudo comparativo do quadro histológico de fígado e baço, com ênfase em granulomas, parasitas, células de Küpffer, células gigantes, reaçäo linforreticular, folículos e amioloidose. O animal revela-se satisftório, como modelo experimetnal, porém de uso limitado, devido ao fenômeno de auto-cura. Isoladamente, anfotericina B é menos eficiente do que quando em associaçöes com levamisole, para a reduçäo do número de parasitas. Animais com amiloidose esplênica apresentam alto número de parasitas. O quadro reativo revela qe a açäo de levamisole, isolada ou combinadamente com anforicina B, induz aumento de defesa com notável incremento da açäo de células fagocitárias