Molecular Imprinting: a promising strategy in matrices elaboration for drug delivery systems

As interações biomoleculares (antígeno-anticorpo, enzima-substrato e fármaco-receptor) há muito tempo têm despertado o interesse de diversos pesquisadores quanto à sua natureza seletiva. Nesse contexto, principalmente a partir de 1940, observa-se uma crescente busca por materiais sintéticos dotados de sítios seletivos de reconhecimento. Hoje, esses materiais encontram-se bem estabelecidos em diversas áreas da ciência como farmácia, química analítica, bioquímica, dentre outras, e são rotineiramente intitulados como polímeros impressos molecularmente (molecularly imprinted polymers-MIP). Embora sua maior aplicação esteja voltada às técnicas de extração/separação, alguns trabalhos têm empregado os MIP como matrizes em sistemas de liberação controlada de fármacos (drug delivery system-DDS), devido ao caráter promissor de tal aplicação e pela facilidade de obtenção desses materiais. Entretanto, o emprego clínico de MIP como DDS ainda é inexistente em decorrência de sua recente aplicação e também pelos extensivos testes que precedem a aprovação de um novo sistema de liberação controlada de fármaco. O objetivo deste trabalho é apresentar os mais recentes avanços no emprego de MIP como DDS reforçando os aspectos mais significativos dessa aplicação, bem como classificando e detalhando esses sistemas quanto aos mecanismos pelos quais o fármaco é liberado.Biomolecular interactions (antigen-antibody, enzyme-substrate and drug-receptor) have been investigated due to their selective nature. Thus, since 1940, the search for synthetic materials presenting specific binding sites has been increasing. Nowadays, they are well established in different science areas such as pharmacy, analytical chemistry, biochemistry, among others, being the referred materials called molecularly imprinted polymers-MIP. Although the largest applications of MIP are found in the separations science field, few applications of these polymers have been reported as drug delivery systems-DDS. Such applications have been promising due to the feasibility of the MIP synthesis. However, the clinical use of the MIP as DDS is still not observed, probably due to its recent application, as well as extensive tests necessary for its approval as a new pharmaceutical form. In this way, this work aims to present the most recent progresses in the use of MIP as DDS, reinforcing the most significant aspects of this application (potentialities and limitations), as well as classifying and detailing such systems

Proteomic analysis of Chromobacterium violaceum and its adaptability to stress

Chromobacterium violaceum (C. violaceum) occurs abundantly in a variety of ecosystems, including ecosystems that place the bacterium under stress. This study assessed the adaptability of C. violaceum by submitting it to nutritional and pH stresses and then analyzing protein expression using bi-dimensional electrophoresis (2-DE) and Maldi mass spectrometry. Chromobacterium violaceum grew best in pH neutral, nutrient-rich medium (reference conditions); however, the total protein mass recovered from stressed bacteria cultures was always higher than the total protein mass recovered from our reference culture. The diversity of proteins expressed (repressed by the number of identifiable 2-DE spots) was seen to be highest in the reference cultures, suggesting that stress reduces the overall range of proteins expressed by C. violaceum. Database comparisons allowed 43 of the 55 spots subjected to Maldi mass spectrometry to be characterized as containing a single identifiable protein. Stress-related expression changes were noted for C. violaceum proteins related to the previously characterized bacterial proteins: DnaK, GroEL-2, Rhs, EF-Tu, EF-P; MCP, homogentisate 1,2-dioxygenase, Arginine deiminase and the ATP synthase β-subunit protein as well as for the ribosomal protein subunits L1, L3, L5 and L6. The ability of C. violaceum to adapt its cellular mechanics to sub-optimal growth and protein production conditions was well illustrated by its regulation of ribosomal protein subunits. With the exception of the ribosomal subunit L3, which plays a role in protein folding and maybe therefore be more useful in stressful conditions, all the other ribosomal subunit proteins were seen to have reduced expression in stressed cultures. Curiously, C. violeaceum cultures were also observed to lose their violet color under stress, which suggests that the violacein pigment biosynthetic pathway is affected by stress. Analysis of the proteomic signatures of stressed C. violaceum indicates that nutrient-starvation and pH stress can cause changes in the expression of the C. violaceum receptors, transporters, and proteins involved with biosynthetic pathways, molecule recycling, energy production. Our findings complement the recent publication of the C. violeaceum genome sequence and could help with the future commercial exploitation of C. violeaceum

The enigma of aluminum deposition in bone tissue from a patient with chronic kidney disease: a case report

sem informaçãoAbout four decades ago, the relationship between dialysis-dementia and aluminum (Al) began to be established. The restriction of drugs containing Al and improvements on water quality used for dialysis resulted in the clinical disappearance of Al intoxicat492201205sem informaçãosem informaçãosem informaçãoThe authors thank Espaço da Escrita - Coordenadoria Geral da Universidade - UNICAMP - for the language services provided, and Wagner Vasques Dominguez for the technical assistanc

Electrophoresis and spectrometric analyses of adaptation-related proteins in thermally stressed Chromobacterium violaceum

Chromobacterium violaceum is a Gram-negative proteobacteria found in water and soil; it is widely distributed in tropical and subtropical regions, such as the Amazon rainforest. We examined protein expression changes that occur in C. violaceum at different growth temperatures using electrophoresis and mass spectrometry. The total number of spots detected was 1985; the number ranged from 99 to 380 in each assay. The proteins that were identified spectrometrically were categorized as chaperones, proteins expressed exclusively under heat stress, enzymes involved in the respiratory and fermentation cycles, ribosomal proteins, and proteins related to transport and secretion. Controlling inverted repeat of chaperone expression and inverted repeat DNA binding sequences, as well as regions recognized by sigma factor 32, elements involved in the genetic regulation of the bacterial stress response, were identified in the promoter regions of several of the genes coding proteins, involved in the C. violaceum stress response. We found that 30°C is the optimal growth temperature for C. violaceum, whereas 25, 35, and 40°C are stressful temperatures that trigger the expression of chaperones, superoxide dismutase, a probable small heat shock protein, a probable phasing, ferrichrome-iron receptor protein, elongation factor P, and an ornithine carbamoyltransferase catabolite. This information improves our comprehension of the mechanisms involved in stress adaptation by C. violaceum. © FUNPEC-RP

Mechanisation in sample preparation by microwaves: the state-of-the-art

This review presents the latest advances of the mechanisation in sample preparation using microwave oven. The fundamental principles of microwaves field interaction with matter are presented, followed by the basic principles of microwave equipment construction. Hyphenation of microwave oven with flow injection analysis or robotic are discussed as well as some metodological difficulties and solutions by its implementation.638643Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Optimization Of A Hydride Generation Metallic Furnace Atomic Absorption Spectrometry (hg-mf-aas) Method For Tin Determination: Analytical And Morphological Parameters Of A Metallic Atomizer.

The present work describes a metallic tube as hydride atomizer for atomic absorption spectrometry. Its performance is evaluated through tin determination, and the accuracy of the method assessed through the analysis of sediment and water samples. Some chemical parameters (referring to the generation of the hydride) such as acid, NaOH and THB concentrations, as well as physical parameters (referring to the transport of the hydride) such as carrier, acetylene, air flow-rates, flame composition, coil length, tube hole area, among others, are evaluated for optimization of the method. Scanning electron microscopy is used for evaluating morphological parameters in both new and used (after 150 h) tube atomizers. The method presents linear Sn concentration from 50 to 1000 µg L(-1) (r>0.9995; n=3) and the analytical frequency of ca. 40 h(-1). The limit of detection (LOD) is 7.1 µg L(-1) and the precision, expressed as RSD is less than 4% (200 µg L(-1); n=10). The accuracy is evaluated through reference materials, and the results are similar at 95% confidence level according to the t-test.117543-

Informações essenciais para a caracterização de um sistema de análise em fluxo Information essential for characterizing a flow-based analytical system

<abstract language="eng">Essential aspects for characterization of a flow-based analytical procedure or system are discussed in order to permit the composition of a checklist that will lead to a protocol for reporting results and systems in flow analysis. Aspects more related to chromatographic procedures are not considered. The intent is to present normalized proposals in the field of flow analysis for practitioners and developers

Improvements In Cobalt Determination By Thermospray Flame Furnace Atomic Absorption Spectrometry Using An On-line Derivatization Strategy.

An on-line derivatization strategy was developed for improving cobalt sensitivity using thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) as the analytical technique. This strategy involves the generation of a volatile cobalt compound, providing better sample vaporization efficiency. The effect of sodium diethyldithiocarbamate (DDTC) as complexing agent on the integrated absorbance signal was evaluated. Parameters including the pH of complex formation, complex concentration and volume, sample volume, flame gas composition and tube atomization configuration were optimized. A wide linear range (from 23 microg L(-1) to 3 mg L(-1); r(2)=0.9786) was obtained, with the best one (r(2)=0.9992) attained from 23 to 400 microg L(-1) with a sample throughput of 30 h(-1). The improvement in the detection power was 17-fold when compared to FAAS, which provides 7 microg L(-1) as the limit of detection when considered TS-FF-AAS technique. A relative standard deviation (n=10) of 4% for a cobalt solution containing 50 microg L(-1) was attained, and the accuracy of the procedure was evaluated through certified reference materials (IAEA-SL-1, lake sediment; and ISS-MURST-A1, Antarctic marine sediment). Good agreement between the results at the 95% confidence level was observed.76475-