Sorption of sulfadiazine on Brazilian soils

AbstractAntimicrobials, among them sulfonamides are widely used in veterinary medicine and can contaminate the environment. The degree to which antimicrobials adsorb onto soil particles varies widely, as does the mobility of these drugs. Sulfadiazine (SDZ) was used to study the adsorption–desorption in Brazilian soil–water systems, using batch equilibrium experiments. Sorption of SDZ was carried out using four types of soils. Adsorption and desorption data were well fitted with Freundlich isotherms in log form (r>0.999) and (0.984<r<0.999), respectively. An adsorption–desorption hysteresis phenomenon was apparent in all soils ranging from 0.517 to 0.827. The experimental results indicate that the Freundlich sorption coefficient (KF) values for SDZ ranged from 0.45 to 2.6μg1−1/n(cm3)1/ng−1

Design of a new molecularly imprinted polymer selective for hydrochlorothiazide based on theoretical predictions using gibbs free energy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to select a suitable functional monomer and a porogenic solvent for the synthesis of the MIP. To confirm the results of the theoretical predictions, three MIPs were synthesized and evaluated using the equilibrium batch rebinding method. A water-compatible MIP was prepared using HCTZ as the template and acrylamide as the functional monomer (FM) with ethylene glycol dimethacrylate as the cross-linker and tetrahydrofuran as the porogen. An imprinting factor of 8.24 was obtained. The polymer was characterized by Fourier transform infrared (FTIR), solid-state nuclear magnetic resonance, scanning electron microscopy, thermogravimetric analysis and nitrogen sorption porosimetry. In addition to HCTZ, six structurally related compounds were tested to evaluate the selectivity of the HCTZ-MIP, and cross-selectivity of the MIP was verified.A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixtur271223002311FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)2007/02306-9141618/2010-8The authors gratefully acknowledge financial support from CNPq (141618/2010-8), FAPESP (2007/02306-9) and FAEPEX-UNICAM

SPR: New tool for biosensors

This paper reviewed the development and theoretical aspects of surface plasmon ressonance (SPR) technique and discusses this powerful sensor technology in the development of biosensors, as well as for the investigation of biological interactions and clinical assays. The SPR has been proven to be a valuable tool to investigate dynamic processes, such as adsorption, degradation, determination of dieletric properties, association/dissociation kinetics, affinity constants of specific ligand-ligate interactions, allowing real-time analysis at almost any surface. The SPR as a complementary technique alongside electrochemical methods is also presented.9710

Antimicrobianos em alimentos de origem vegetal - uma revisão

Doenças de origem bacteriana em frutas e hortaliças ocorrem no campo ou após a colheita, reduzem a produção e afetam a qualidade do produto para a comercialização e, muitas vezes, causam prejuízos econômicos elevados ao agricultor. O alto teor de água de frutas e hortaliças torna esses vegetais sensíveis ao ataque de bactérias. Para prevenir as perdas econômicas decorrentes de doenças bacterianas em alimentos de origem vegetal, o controle químico é feito com o uso de bactericidas agrícolas como a oxitetraciclina e estreptomicina. Esta revisão tem por objetivo abordar os antimicrobianos permitidos pela legislação brasileira para o uso em lavouras, assim como aspectos de legislação e de métodos analíticos utilizados para avaliação da presença de resíduos dos antimicrobianos em vegetais

Electrochemical behavior of N-nitrosothiazolidine carboxilic acid on gold and mercury electrodes

The electrochemical behavior of N-nitrosothiazolidine carboxylic acid (NTAC) on gold and hanging mercury electrodes, using the cyclic and square wave voltammetries, was studied. Whereas NTAC suffer reduction in a single step on the mercury electrode, two peaks appears on the cyclic voltammograms on the gold electrode, one anodic peak overlaying the gold oxide process at 1.2 V and one cathodic peak at -0.41 V vs Ag/AgCl, KCl 3.0 mol L-1. The cathodic peak depends on the previous oxidation of NTAC at the electrode surface, presents irreversible and adsorption controlled characteristics and it is suitable for quantitative purposes.10671072Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Considerations and practical implications of the guide for validation and analytical quality control of drugs in feed and veterinary drugs

Recently, the Brazilian Ministry of Agriculture, Livestock and Supply (MAPA) published a validation and analytical quality control guide called the “Guia de Validação e Controle de Qualidade Analítica – Fármacos em Produtos para Alimentação Animal e Medicamentos Veterinários”, in order to guide officers and accredited laboratories in the validation of analytical methods for the quality control of veterinary medicines, drug contaminants in feed and depletion studies (residues of drugs in biological matrices). The aim of this study was to present a critical evaluation of the concepts and procedures defined in this document. The Guide was applied for the validation of chromatographic methods intended to be used for the quantification of antimicrobial and antiparasitic drugs in veterinary medicines. Methods for the determination of ivermectin, abamectin, sulfadiazine, sulfadimethoxine, sulfaquinoxaline, streptomycin, dihydrostreptomycin and florfenicol were validated using the Guide. Each validation parameter was evaluated and discussed. A total of 55 samples of veterinary drugs were analyzed385697708CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP064/2008; 457417/2012-9; 350404/2014-32009/10443-1; 2013/09543-

GC-MS determination of organochlorine pesticides in medicinal plants harvested in Brazil

A method using Gas Chromatography coupled to Mass Spectrometry (GC-MS) for the determination of hexachlorobenzene, lindane, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, 4,4'-DDT and 4,4'-DDE in leaves of Mikania laevigata, Maytenus ilicifolia and Cordia verbenacea was developed. Extraction of the pesticides was carried out by solid-liquid extraction (SLE), followed by clean-up in solid phase mixed cartridge (Florisil and silica-gel). Quantification was performed using GC-MS in the selected ion monitoring mode. Mean recovery rates of 70 to 124% were obtained. The inter-assay precision of a sample fortified with 200 ng g-1 of each pesticide was in the range of 1.0 to 7.3%. The quantitation limits ranged from 3.0 to 30 ng g-1 and were below the Maximum Residue Limit (MRL) for all the pesticides under study. The method was employed to analyze samples of Mikania laevigata, Maytenus ilicifolia and Cordia verbenacea from an experimental field in Paulínia, SP, Brazil. The samples presented contamination with dieldrin above the MRL established by the European Pharmacopoeia (50 ng g-1)

Occurrence, behavior and environmental impacts caused by the presence of veterinary antimicrobials in soils

Antimicrobials, among other veterinary drugs, are used worldwide in industry and agriculture to protect animal health and prevent economic loss. In recent years, they have been detected in various environmental compartments, including soil, surface and groundwater and have become a topic of research interest. Emphasizing this class of compounds, this review presents the different pathways which veterinary drugs enter in the environment, in particular contaminate soils. Also are presented regulatory aspects and guidelines, adsorption/desorption and degradation of these compounds in soils and the consequences of its dispersal in the environment.159169Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP