Caracterização físico-química de complexo de inclusão entre hidroximetilnitrofurazona e hidroxipropil-beta-ciclodextrina

Hydroxymethylnitrofurazone (NFOH) is a prodrug that is active against Trypanosoma cruzi. It however presents low solubility and high toxicity. Hydroxypropyl-beta-cyclodextrin (HP-beta-CD) can be used as a drug-delivery system for NFOH modifying its physico-chemical properties. The aim of this work is to characterize the inclusion complex between NFOH and HP-beta-CD. The rate of NFOH release decreases after complexation and thermodynamic parameters from the solubility isotherm studies revealed that a stable complex is formed (deltaGº= 1.7 kJ/mol). This study focuses on the physico-chemical characterization of a drug-delivery formulation that comes out as a potentially new therapeutic option for Chagas disease treatment.

Síntese de beta-N-acetilglicosaminídeos de arila modificados em C-6 como potenciais agentes antimicrobianos

We report herein the synthesis of aryl beta-N-acetylglucosaminides containing azido, amino and acetamido groups at C-6 as potential antimicrobial agents. It was expected that these compounds could interfere with the biosynthesis and/or biotransformation of N-acetylglucosamine in fungi and bacteria. None of the compounds showed antimicrobial activity against bacteria (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), filamentous fungus (Aspergillus niger) and yeasts (Saccharomyces cerevisae, Candida albicans and Candida tropicallis), at the concentration of 1 mg/mL in agar diffusion assay.

Ondas ultrassônicas e pérolas de vidro: um novo método de extração de beta-galactosidase para uso em laboratório

The optimization of a traditional technique of cellular disruption by abrasion was carried out and a process using ultrasonic waves associated with glass pearls to extract beta-galactosidase from Kluyveromyces marxianus proposed. In the first case, the effects of the diameter and weight of the pearls in relation to the volume of cellular suspension and amount of time for cellular disruption were evaluated. The efficiency of the new process of cellular disruption was evaluated by varying the length of time of sonification and comparing with the method of abrasion under the same conditions. The proposed method can be efficiently applied to obtain beta-galactosidase at laboratory scale.

Propriedades e aplicações recentes das ciclodextrinas

Cyclodextrins (CDs) are cyclic oligosaccharides comprised of six or more glucose units connected by alpha-1,4 bonds. They have hydrophobic cavities with a hydrophilic exterior, and are versatile receptors for a variety of substrates. This ability allows them to be applied in many fields, as distinct as supramolecular chemistry, nanotechnology, pharmaceuticals, green chemistry, agrochemicals, analytical chemistry, toiletries, foods, and cosmetics. This review summarizes several aspects related to the physico-chemical properties of CDs and discusses their potential applications illustrated by recent examples. The prospects for their use in several areas are also described.

Purificação e caracterização da beta-lapachona e estudo de estabilidade dos cristais em diferentes condições de armazenamento

The beta-lapachone is a product obtained from the Ipê Roxo tree [Tabebuia avellandae], which has proved its excellent antineoplasic potential acting through a particular mechanism of apoptosis against various cancer types. This study aims at determining the identity card of beta-lapachone by means of physico-chemical and pharmaco-technical characterization. A purifying process has been performed, as well as the isolation of a contaminant, its isomer alpha-lapachone. A stability study was also performed, determining the ideal storing conditions for beta-lapachone, essential for the ongoing pre-formulation studies for obtaining the different classic pharmaceutical forms and modified release systems.

Produção, purificação e aumento da performance de ciclodextrina glicosiltransferases para produção de ciclodextrinas

Biospecific affinity chromatography was used to purify three cyclodextrin glycosyl transferases (CGTases) obtained from microorganisms isolated of soil. The cyclodextrins (CDs) production by CGTases was evaluated using starches from different sources. CDs were measured through the Complexation Theory and by HPLC. CGTase from Bacillus firmus strain 7B showed the best production (30 mmol/L of β-CD and 4.3 mmol/L of γ-CD), and its cultivation conditions were optimized. The maximum enzymatic activity was achieved using lung peptone, soluble starch and agitation speed of 160 rpm. Studied CGTases were shown quite interesting for the industrial production of CDs.

Aplicação de ciclodextrinas em processos têxteis

Cyclodextrins (CDs) are water soluble cyclic sugars with a hydrophobic nanometric cavity that permits the formation of host/guest inclusion complexes with a large variety of molecules, alternating their physical-chemical properties. In the present review CD research related to the processing of textiles is revised and discussed. CDs may function as encapsulating, dispersing and levelling agents in the dyeing and washing of textiles. Furthermore they may be anchored to polymers and textile fibers in order to impart special properties such as odor reduction, UV protection or for the controlled release of perfumes, aromas, mosquito repellents or substances with therapeutical effects.

Cristalización de zeolita beta mediante conversión asistida por vapor: influencia de los parámetros de síntesis

In the present work, beta zeolites were prepared by an alternative route called steam-assisted conversion (SAC). Several zeolites were synthesized using amorphous dry gels with a low SDA concentration (0.09 mol, TEAOH). Temperature and crystallization time were the main parameters studied. X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM) were the characterization techniques employed. The zeolites prepared showed mixed phases such as beta, MTW and ZSM-5 while only one sample treated at 150ºC with 24 h of crystallization time showed a pure ZSM-5 phase (SAC-5). These preliminary results serve as a starting point for optimizing the synthesis of a specific type of zeolite using the SAC method.

Quantification of beta-lactam antibiotics in veterinary drugs: amoxicillin and ampicillin determination by high performance liquid chromatography

This work focused on the development and validation of an RP-HPLC-UV method for quantification of beta-lactam antibiotics in three pharmaceutical samples. Active principles analyzed were amoxicillin and ampicillin, in 3 veterinary drugs. Mobile phase comprised 5 mmol L-1 phosphoric acid solution at pH 2.00, acetonitrile with gradient elution mode and detection wavelength at 220 nm. The method was validated according to the Brazilian National Health Surveillance regulation, where linear range and linearity, selectivity, precision, accuracy and ruggedness were evaluated. Inter day precision and accuracy for pharmaceutical samples 1, 2 and 3 were: 1.43 and 1.43%; 4.71 and 3.74%; 2.72 and 1.72%, respectively, while regression coefficients for analytical curves exceeded 0.99. The method had acceptable merit figure values, indicating reliable quantification. Analyzed samples had active principle concentrations varying from -12 to +21% compared to manufacturer label claims, rendering the medicine unsafe for administration to animals.

Glicerol como solvente verde em eficiente obtenção de beta-hidroxiésteres

In this work, we report a new method for obtaining racemic β-hydroxyesters by reduction of β-ketoesters. The use of glycerol as a reactional medium in selective reduction of β-ketoesters into the corresponding alcohols was shown to be a viable and more efficient alternative compared with the conventional methodology, taking into account green chemistry prerogatives.

OBTENÇÃO E CARACTERIZAÇÃO DE MATERIAL HÍBRIDO ENTRE SÍLICA E CICLODEXTRINAS

The obtention of silica and cyclodextrin hybrid materials was accomplished by refluxing them in xylol using citric acid as a binding agent. The materials were characterized by infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and elemental analysis. Evidence for the docking of cyclodextrins α and γ was substantiated based on the variation in band intensity for groups such as ≡Si-OH. Additional docking evidence includes the displacement of some of the bands that are related to cyclodextrin such as the deformation of the C-H axial bond. The α and γ-CDSi materials were characterized as amorphous compounds. The products obtained in the synthesis showed changes in the decomposition temperatures of their isolated constituents, in which the mass of α and γ-CD docked to the silica surface gave the estimated values of 41% and 47%, respectively. The elemental constituents were shown to be consistent and close to their relative theoretical values. ​Thermogravimetric analysis showed that a reduction in the percentage of the hybrids was proportional to the amount of lost mass. This new material is an improvement over synthesized organosilane materials because the operator and the environment benefit from a less toxic methodology. In addition, the material has several potential applications in complexation systems with cyclodextrin.

Proteção a murcha de fusário do tomateiro com Acibenzolar-S-Metil e Ácido beta-Aminobutírico, em campo

Os elicitores abióticos são compostos que induzem a síntese de fitoalexinas, como também outras respostas de defesa da planta. Visando a obtenção de uma alternativa de controle para murcha de fusário do tomateiro (Lycopersicon esculentum) foram avaliados os indutores Acibenzolar-S-Metil (ASM) e Ácido beta-Aminobutírico (BABA), em diferentes doses e épocas de aplicação via foliar. Foram utilizadas as cultivares Viradoro e IPA-6, suscetíveis a raça 1 de Fusarium oxysporum f.sp. lycopersici. A avaliação de sintomas externos foi realizada semanalmente e a avaliação final realizada aos 43 dias após a inoculação das plantas, através da análise de sintomas externo e interno, utilizando-se duas escalas de notas. Apenas na cv. IPA-6 houve redução no índice de doença no tratamento com BABA na maior dose, aplicado cinco dias antes da inoculação.

Extração do corante da beterraba (Beta vulgaris) para utilização como indicador ácido-base

No presente trabalho, foi investigado o comportamento do extrato aquoso e alcoólico da beterraba (Beta vulgaris) como um indicador ácido-base, tendo como objetivo principal despertar o interesse pelo uso dos indicadores naturais, como alternativa didática para transmissão dos conceitos de titulação, equilíbrio químico e a lei de Lambert-Beer. Para a realização dos experimentos foram utilizadas soluções padrão de ácido clorídrico (HCl), ácido acético e hidróxido de sódio (NaOH). Inicialmente foram feitos testes para avaliar a reversibilidade do sistema, e observou-se que a coloração passa de vermelho para amarela com adição de base e retorna para vermelho com adição do ácido, sendo possível sua utilização para explicação do equilíbrio químico. As análises de espectroscopia UV-vis mostraram que os espectros de absorção molecular na região do visível, apresentam diferentes característica, dando indícios que ocorreu modificação na estrutura do indicador em meio ácido e básico. Após as análises volumétricas constatou-se que os pontos de equivalência determinados com o indicador natural tiveram concordância com os obtidos pelo método potenciométrico. Além disso, os extratos aquosos e alcoólicos da beterraba apresentam potencial didático para a explicação da lei de Lambert-Beer, sendo que no meio ácido houve uma melhor correlação comparado com o meio básico.

Expressão do P16 e do PDGFR-Beta no adenocarcinoma gástrico

OBJETIVO: Detectar a expressão imunoistoquímica do p16 e do PDGFR-beta no adenocarcinoma gástrico. MÉTODOS: Foram estudados 36 pacientes submetidos a cirurgia para adenocarcinoma gástrico entre 1998 e 2002 no Hospital da Santa Casa de Porto Alegre. As variáveis investigadas foram: idade, sexo, tamanho e localização do tumor, número de linfonodos dissecados, número de linfonodos metastáticos, tipo histológico, extensão da ressecção cirúrgica e estadiamento patológico. RESULTADOS: Não foi detectada expressão do PDGFR-beta nas peças cirúrgicas. Em relação ao p16, detectou-se perda de expressão menor que 10% e menor que 1% respectivamente em 89% e 79% das peças estudadas. CONCLUSÃO: Não houve correlação entre a perda de p16 e as variáveis estudadas.

Triploidia fetal associada à diminuição da subunidade beta e do estriol não-conjugado no soro materno

Relatamos um caso de triploidia fetal não-molar detectada na 20ª semana gestacional por cordocentese realizada em razão de estudo ultra-sonográfico que revelou retardo do crescimento intra-uterino e grave oligoidrâmnio. Na 19ª semana foram verificados acentuada diminuição da subunidade beta livre da gonadotrofina coriônica humana e do estriol não-conjugado e níveis de alfa-fetoproteína normais, apontando para um risco aumentado de síndrome de Edwards. Houve morte fetal um dia após a cordocentese e a resolução do caso foi por parto vaginal induzido com misoprostol e ocitocina, sob analgesia peridural. Estudo cromossômico das células sangüíneas fetais revelou o cariótipo 69,XXX. O grave retardo do crescimento intra-uterino, a macrocefalia, constatada no estudo anatomopatológico do feto, e os níveis muito baixos de hCG e de estriol não-conjugado sugerem um caso de triploidia por diginia, fertilização de um óvulo diplóide por um espermatozóide haplóide.