Projeto e construção de um picnômetro a ar para caracterização de insumos e produtos farmacêuticos

This paper describes a project, construction and test of a low cost air pycnometer, developed to be used preferentially in pharmaceutical research. A complete discussion of the construction, test and calibration of this equipment is presented and some measurements are made using pharmaceutical powders and dry granulations. The equipment performance has been estimated through its calibration curve, and the obtained value to its volume resolution is about 1%. This equipment is accomplished at the Applied Nuclear Physics Laboratory of University of Sorocaba (LAFINAU) in Sorocaba, SP, Brazil and it was denominated "Picnômetro a Ar Uniso - PICNAU".

Oligômeros e polímeros derivados do tiofeno: síntese e aplicações

In this review we summarize recent synthetic investigations about the preparation of oligothiophenes and polythiophenes, the most important π-conjugated organic materials for applications in electrochromic and electroluminescent devices. It is showed that many interesting and novel functionalized oligothiophenes have been synthesized by convenient coupling strategies (Heck, Kumada, Negishi, Suzuki, Stille and Ullmann) and oxidative coupling methods. Synthesis of polythiophenes are also presented and described according to chemical and electrochemical polymerization methodologies. The description of these noteworthy synthetic methods illustrates how important and promising are the interdisciplinary approaches in the obtaining of oligothiophenes and polythiophenes.

Derivados citotóxicos de vitanolidos isolados das folhas de Acnistus arborescens

In view of anticancer activity of 7 β-acetoxywithanolide D (2) and 7β-16α-diacetoxywithonide D (3), isolated from the leaves of Acnistus arborescens (Solanaceae), five withanolide derivatives were obtained and their structures were determined by NMR, MS and IV data analysis. The in vitro anticancer activity of these derivatives was evaluated in a panel of cancer cell lines: human breast (BC-1), human lung (Lu1), human colon (Col2) and human oral epidermoid carcinoma (KB). Compounds 2a (acetylation of 2), 3b (oxidation of 3) and 2c (hydrogenation of 2) exhibited the highest anticancer activity against human lung cancer cells, with ED50 values of 0.19, 0.25 and 0.63 μg/mL, respectively.

Adsorção do corante vermelho congo por derivados da o-carboximetilquitosana hidrofobicamente modificados

Hydrophobically modified O-carboxymethylchitosan derivatives were synthesized through a reaction with lauroyl chloride and applied for adsorption of congo red dye. The Langmuir-Freundlich isotherm model was found to be the most suitable one for the VC adsorption and maximum adsorption capacity obtained was 281.97 mg g-1 at a pH value of 7.0 for HL 1.0. The adsorption process follows the pseudo-second-order kinetics and the corresponding rate constants were obtained. The thermodynamic parameters showed that adsorption process is spontaneous (positive ∆Hº) and favorable (negative ∆Gº). The hydrophobic derivatives are able to adsorb the dye even in high pH values.

Desenvolvimento e validação de método analítico para determinação de benzoato, sorbato, metil e propilparabenos em produtos alimentícios utilizando a eletroforese capilar

In this work, a rapid and simple method using capillary electrophoresis (CE) was developed for the determination of the benzoate, sorbate, methyl and propylparaben in foodstuffs. A running buffer consisting of 20 mmol L-1 (pH = 9.3) tetraborate enabled separation of the analytes in less than 5 min. The detector wavelength was set at 220 nm. The method was successfully applied to the analysis of sodas, sweeteners, sauces and juices. The range of preservatives found were from 478.5-466.6 mg kg-1 for methylparaben , 83.7-231.3 mg kg-1 for sorbate and 336.7-428.3 mg kg-1 for benzoate.

Do engenho à biorrefinaria: a usina de açúcar como empreendimento industrial para a geração de produtos bioquímicos e biocombustíveis

A sugar cane mill is at the present moment a modest biorefinery producing few products such as sugar, ethanol and polyhydroxybutyrate (PHB). In the near future, this mill can expand its production using several renewable feedstock's to produce biofuels and high value biobased chemicals. However, the choice of appropriate products for addition to the portfolio is challenged by a lack of broad-based conversion technology coupled with a plethora of potential targets. The intent of this revision was to catalyze research efforts to expand the list of products and to present an updated evaluation of potential target structures for chemical production.

Definição de shelf life para produtos químicos: a importância de um guia de estabilidade específico para o segmento

The chemical industries worldwide are passing through a very particular moment of re-adaptation due to the implementation of an European regulation called, Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). In Brazil, the Brazilian Chemical Industry needs urgently a specific guide of chemical products stability. The main purpose of this work is to present a proposal of a guide of stability for chemical products based on the reference guides of the International Conference on Harmonization (ICH). Thus, this work proposes an innovation in terms of methodology which will be useful for shelf life definition purpose for chemical industry products.

Estudos de QSAR 2D baseados em descritores topológicos e fragmentos moleculares para uma série de derivados azólicos ativos contra Candida albicans

Azole derivatives are the main therapeutical resource against Candida albicans infection in immunocompromised patients. Nevertheless, the widespread use of azoles has led to reduced effectiveness and selection of resistant strains. In order to guide the development of novel antifungal drugs, 2D-QSAR models based on topological descriptors or molecular fragments were developed for a dataset of 74 molecules. The optimal fragment-based model (r² = 0.88, q² = 0.73 and r²pred = 0.62 with 6PCs) and descriptor-based model (r² = 0.82, q² = 0.79 and r²pred = 0.70 with 2 PCs), when analysed synergically, suggested that the triazolone ring and lipophilic properties are both important to antifungal activity.

Utilização de detecção por espalhamento de luz evaporativo para a análise de produtos naturais

The interest in the use of evaporative light scattering detector (ELSD) for the analysis of different classes of natural products has grown over the years. This is because this detector has become an excellent alternative compared to other types of detectors, such as the refractive index detector and the ultraviolet (UV) detector. This review describes the basic principles of ELSD functioning and discusses the advantages and disadvantages in using an ELSD for the analysis of organic compounds. Additionaly, an overview, covering the last 23 years, of ELSD applications in natural products analysis (saponins, terpenes, carbohydrates, glycosides, alkaloids, steroids, flavonoids, peptides, polyketides, coumarins and iridoids) is presented and discussed.

Síntese e caracterização de copolímeros de cadeia lateral derivados de acrilatos de 4,5-di-hidroisoxazol e do (-)-mentol

Five monomers 5-[4-(5-cyano-4,5-dihydroisoxazol-3-yl)phenoxy]undecyl acrylate (7a); n-alkyl 3-{4-[5-(acryloyloxyundecyl)oxyphenyl]}-4,5-dihydroisoxazole-5-carboxylate (7b,c for n-butyl and n-hexyl, respectively); 3-{4-[5-(acryloyloxyundecyl) oxyphenyl]}-4,5-dihydroisoxazole-5-carboxylic acid (7d) and (1R,2S,5R)-2-isopropyl-5-methylcyclohexyl acrylate (9) and the corresponding copolymers 10a-d,11 and homopolymers 12 from 7a and 13 from 9 were designed and synthesized. Except for acrylate 9 which is derived from (-)-menthol, all of the monomers belong to the series containing the isoxazoline ring linked to the acrylate unit by a flexible spacer chain of eleven methylene units. They presented low glass temperature and despite birefringence behavior, these copolymers showed no mesomorphic properties.

Síntese e avaliação preliminar da atividade antibacteriana e antifúngica de derivados N-acilidrazônicos

We describe the synthesis and evaluation of N-acylhydrazone compounds bearing different electron-donating groups in one of its aromatic rings, obtained using a four-step synthetic route. IC50 values against pathogenic fungi and bacteria were determined by serial microdilution. Compounds showed low activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. By contrast, a derivative with a meta-oriented electron-donating group showed significant activity (IC50) against Candida albicans (17 µM), C. krusei (34 µM) and C. tropicalis (17 µM). Results suggest this is a promising lead-compound for synthesis of potent antifungal agents.

Determinação de compostos carbonilados e carboxilados em derivados de petróleo

Although metals and nitrogen/sulfur compounds have been the main concern of the petroleum industry, issues concerning the harmful effects on catalysts poisoning and product contamination by other contaminants such as oxygen-containing compounds have been raised. Trace amounts of carbonyl and carboxyl compounds in petroleum products can lead to catalyst poisoning. Additionally, oxygenates may be present in final polyethylene and polypropylene resins, affecting the quality of food packaging. In this work, we reviewed potential analytical approaches for oxygenates determination in petroleum products and report the features of each potential technique.

Isolamento e avaliação do potencial citotóxico de derivados fenólicos de Schinus terebinthifolius Raddi (Anacardiaceae)

The EtOH extract from leaves of S. terebinthifolius was subjected to partition between EtOH:H2O and hexane, CH2Cl2, and EtOAc. The phases obtained were evaluated in vitro against human tumoral cell lines and the EtOAc phase exhibited activity. Chromatographic procedures afforded gallic acid (1), methyl (2) and ethyl (3) gallates, trans-catechin (4), quercitrin (5), and afzelin (6), being the first occurrence of 1, 4 and 6 in S. terebinthifolius.In vitro cytotoxic evaluation of 1 - 6 indicated that gallic acid (1) displayed higher activity than ethyl gallate (3) against HL-60 and HeLa cells, while compounds 2, 4 - 6 were inactive.

Síntese de heterociclos bioativos derivados do ferroceno

The discovery of ferrocene marked one of the points of departure for modern organometallic chemistry. In general, the compounds of ferrocene derivatives are widely applied in several areas. One of the most important applications of ferrocene is the development of more active drugs, especially in cases where there is resistance to current drugs. Bioactive agents containing ferrocene have proven effective in combating diseases such as cancer, malaria, HIV, Alzheimer and conditions caused by fungi and bacteria. In this context, the present paper aims to highlights the synthesis of heterocycles containing ferrocene moiety and their use in medicinal chemistry.

Preparação de derivados do lapachol em meio ácido e em meio básico: uma proposta de experimentos para a disciplina de Química Orgânica Experimental

In this educational paper we describe the extraction of lapachol from its natural source according to acid-base concepts in organic chemistry and the use of its derivatives β-lapachone and hydroxy-hydrolapachol to exemplify intramolecular cyclization, carbocation stability, Michael addition reaction and chromatography. The experiments were performed during three different undergraduate organic chemistry laboratory classes using low cost material, while avoiding color reagents for TLC visualization, as well as small-scale column chromatography to isolate the mixture of lapachol and β-lapachone.