Piroxicam encapsulated in liposomes: Characterization and in vivo evaluation of topical anti-inflammatory effect

Liposomes of soya phosphatidylcholine, cholesterol, and stearylamine (molar ratio 6/3/1) and 0.1% alpha-tocopherol were prepared by the extrusion of multilamellar vesicles through 0.2-mu m polycarbonate membrane. Liposomes were characterized by electron transmission microscopy, and the mean structure diameter was 278 nm. The encapsulation efficiency obtained was 12.73%. The topical anti-inflammatory effect was evaluated in vivo by the cotton pellet granuloma method. We analyzed free piroxicam at 4 mg/kg, piroxicam encapsulated in liposomes added to 1.5% hydroxyethylcellulose (HEC) gel at 1.6 mg/kg, and piroxicam encapsulated in liposomes added to HEC gel at 4 mg/kg; the inhibition of inflammation obtained was 21.1%, 32.8%, and 47.4%, respectively. These results showed that the encapsulation of piroxicam produced an increase of topical anti-inflammatory effect, suggesting that the inhibition of inflammation can be obtained with lower drug concentrations.

Preparation and characterization of free films of high amylose/pectin mixtures cross-linked with sodium trimetaphosphate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Protective effect of beta-glucan extracted from Saccharomyces cerevisiae, against DNA damage and cytotoxicity in wild-type (k1) and repair-deficient (xrs5) CHO cells

A large number of functional foods, including those that contain P-glucan, have been shown to prevent the development of cancer and other chronic diseases. The aim of the present study was to elucidate its mechanism of action, as well as to understand its effects as an antigenotoxic, anticlastogenic agent, and to determine its capacity to preserve cell viability. The investigation was carried out in the CHO-k1 and CHO-xrs5 cell lines. The cytokinesis-blocked micronucleus assay indicated that the different doses of beta-glucan examined (5, 10, 20 and 40 mu g/ml) did not show clastogenic effects. In the CHO-k1 cell line, a chemopreventive effect could be observed in all the protocols tested: pre-treatment (% reduction of 35.0-57.3), simultaneous treatment (simple - 5 reduction of 19.7-55.6 and with pre-incubation - of 42.7-56.4) and post-treatment (% reduction of 17.9-37.6). This finding indicates mechanisms of action involving desmutagenesis and bio-antimutagenesis, albeit the latter having a lesser role. However, in the repair-deficient CHO-xrs5 cells, beta-glucan did not show a protective effect with post-treatment (% reduction of 2.96), thus supporting the involvement of bioantimutagenesis. The comet assay in CHO-k1 cells demonstrated that beta-glucan has neither a genotoxic nor an antigenotoxic effect. Cell viability tests indicated that beta-glucan preserves cell viability in both cell lines, preventing apoptotic events. These findings suggest that beta-glucan, when present in foods, could provide them with nutraceutical characteristics and act as a dietary supplement, or that P-glucan could be used in new drug development. (c) 2006 Elsevier Ltd. All rights reserved.

Determining the structural basis for specificity of ligands using crystallographic screening

Crystallographic screening has been used to identify new inhibitors for potential target for drug development. Here, we describe the application of the crystallographic screening to assess the structural basis of specificity of ligands against a protein target. The method is efficient and results in detailed crystallographic information. The utility of the method is demonstrated in the study of the structural basis for specificity of ligands for human purine nucleoside phosphorylase (PNP). Purine nucleoside phosphorylase catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. This enzyme is a target for inhibitor development aiming at T-cell immune response modulation and has been submitted to extensive structure-based drug design. This methodology may help in the future development of a new generation of PNP inhibitors.

Molecular models of NS3 protease variants of the Hepatitis C virus

Background: Hepatitis C virus (HCV) currently infects approximately three percent of the world population. In view of the lack of vaccines against HCV, there is an urgent need for an efficient treatment of the disease by an effective antiviral drug. Rational drug design has not been the primary way for discovering major therapeutics. Nevertheless, there are reports of success in the development of inhibitor using a structure-based approach. One of the possible targets for drug development against HCV is the NS3 protease variants. Based on the three-dimensional structure of these variants we expect to identify new NS3 protease inhibitors. In order to speed up the modeling process all NS3 protease variant models were generated in a Beowulf cluster. The potential of the structural bioinformatics for development of new antiviral drugs is discussed.Results: the atomic coordinates of crystallographic structure 1CU1 and 1DY9 were used as starting model for modeling of the NS3 protease variant structures. The NS3 protease variant structures are composed of six subdomains, which occur in sequence along the polypeptide chain. The protease domain exhibits the dual beta-barrel fold that is common among members of the chymotrypsin serine protease family. The helicase domain contains two structurally related beta-alpha-beta subdomains and a third subdomain of seven helices and three short beta strands. The latter domain is usually referred to as the helicase alpha-helical subdomain. The rmsd value of bond lengths and bond angles, the average G-factor and Verify 3D values are presented for NS3 protease variant structures.Conclusions: This project increases the certainty that homology modeling is an useful tool in structural biology and that it can be very valuable in annotating genome sequence information and contributing to structural and functional genomics from virus. The structural models will be used to guide future efforts in the structure-based drug design of a new generation of NS3 protease variants inhibitors. All models in the database are publicly accessible via our interactive website, providing us with large amount of structural models for use in protein-ligand docking analysis.

Electrochemical, Spectrophotometric and Liquid-Chromatographic Approaches for Analysis of Tropical Disease Drugs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Preparation and antimicrobial activity of gelatin microparticles containing propolis against oral pathogens

Gelatin microparticles containing propolis ethanolic extractive solution were prepared by spray-drying technique. Particle,, with regular morphology, mean diameter ranging of 2.27 mu m to 2.48 mu m, and good entrapment efficiency for propolis were obtained. The in vitro antimicrobial activity of microparticles was evaluated against microorganisms of oral importance (Enterococcus faecalis, Streptococcus salivarius, Streptococcus sanguinis, Streptococcus mitis, Streptococcus mutans, Streptococcus sobrinus, Candida albicans, and Lactobacillus casei). The utilized techniques were diffusion in agar and determination of minimum inhibitory concentration. The choice of the method to evaluate the antimicrobial activity of microparticles showed be very important. The microparticles displayed activity against all tested strains of similar way to the propolis, showing greater activity against the strains of E. salivarius, S. sanguinis, S. mitis, and C albicans.

Determination of oligoelements in parenteral formulations by planar chromatography and spectrophotometry

The authors have studied the chromatographic behavior of parenteral preparations for pediatric use containing inorganic cations. After separation and identification by thin-layer chromatography, Mn2+, Zn2+, and Cu2+ were analyzed by a method based on reaction with an appropriate reagent and extraction with an organic solvent which yielded elution and preconcentration, resulting in an appropriate solution for colorimetric quantitation. Cr3+ cation was determined by atomic absorption spectrophotometry after appropriate chromatographic separation, using microcrystalline cellulose (adsorbent) and an acetone:water:hydrochloric acid mixture (80:5:8) as the mobile phase.

Tissue tolerance of diclofenac sodium encapsulated in liposomes after intramuscular administration

In this work the effect of the encapsulation of diclofenac sodium within liposomes on the reduction of the myotoxicity after intramuscular administration in rats was studied. Diclofenac sodium was encapsulated in small unilamellar liposomes obtained from phosphatidylcholine, cholesterol, and a-tocopherol (40:10:0.04 mM), and administered by intramuscular injection in the quadriceps femoral muscle of male Wistar rats. After a single dose of 0.2 mg diclofenac formulations the local tissue damage was assessed by plasma creatine kinase (CPK) activity and histological analysis. It was demonstrated that formulations containing free diclofenac produced a higher increase in CPK activity, while those encapsulated in liposomes exhibited CPK activity similar to the control groups. Histopathological analysis of local muscle tissue performed on the third and seventh days following the injection showed intense cellular damage when free drug solution was used, while encapsulation in liposome protected the tissue against the local tissue inflammation.

Effect of the dibenzylbutyrolactone lignan (-)-hinokinin on doxorubicin and methyl methanesulfonate clastogenicity in V79 Chinese hamster lung fibroblasts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of drying technique on some physical properties of cross-linked high amylose/pectin mixtures

Polymers mixtures as well as cross-linking reactions are approaches that have been used successfully to modulate the polymers characteristics in order to improve the control over drug release rate. High amylose and pectin are polysaccharides frequently used to prepare drug delivery systems. Since the drying technique can strongly influence the properties of such systems, the aim of this work was to characterize high amylose/pectin mixtures cross-linked with sodium trimetaphosphate and dried by different techniques-oven and lyophilization. The results showed that samples dried by lyophilization presented reduced particle size, higher porosity and higher swelling ability than the samples dried in oven. Besides, lower thermal stability and different diffraction patterns showed by the former particles should reflect the structural changes as a function of drying technique. © 2013 Informa Healthcare USA, Inc.

A success in Toxinology translational research in Brazil: Bridging the gap

Basic research is fundamental for discovering potential diagnostic and therapeutic tools, including drugs, vaccines and new diagnostic techniques. On this basis, diagnosis and treatment methods for many diseases have been developed. Presently, discovering new candidate molecules and testing them in animals are relatively easy tasks that require modest resources and responsibility. However, crossing the animal-to-human barrier is still a great challenge that most researchers tend to avoid. Thus, bridging this current gap between clinical and basic research must be encouraged and elucidated in training programmes for health professionals. This project clearly shows the challenges faced by a group of Brazilian researchers who, after discovering a new fibrin sealant through 20 years of painstaking basic work, insisted on having the product applied clinically. The Brazilian government has recently become aware of this challenge and has accordingly defined the product as strategic to the public health of the country. Thus, in addition to financing research and development laboratories, resources were invested in clinical trials and in the development of a virtual platform termed the Virtual System to Support Clinical Research (SAVPC); this platform imparts speed, reliability and visibility to advances in product development, fostering interactions among sponsors, physicians, students and, ultimately, the research subjects themselves. This pioneering project may become a future model for other public institutions in Brazil, principally in overcoming neglected diseases, which unfortunately continue to afflict this tropical country. © 2013 Elsevier Ltd.

Avaliação do potencial tripanocida dos óleos essenciais de Melampodium divaricatum e Hedychium coronarium e dos extratos de Polygonum ferrugineum em cepas de Trypanosoma brucei

Pós-graduação em Biotecnologia - IQ

Estudo das estruturas terciária e quaternária de proteínas por espalhamento de raios X a baixos ângulos integrado a técnicas de modelagem

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)