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Search Results: 1 - 10 of 117329 matches for " Raul Cesar;Gremi?o "
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Mucoadhesive drug delivery systems
Carvalho, Flávia Chiva;Bruschi, Marcos Luciano;Evangelista, Raul Cesar;Gremio, Maria Palmira Daflon;
Brazilian Journal of Pharmaceutical Sciences , 2010, DOI: 10.1590/S1984-82502010000100002
Abstract: drug actions can be improved by developing new drug delivery systems, such as the mucoadhesive system. these systems remain in close contact with the absorption tissue, the mucous membrane, releasing the drug at the action site leading to a bioavailability increase and both local and systemic effects. mucoadhesion is currently explained by six theories: electronic, adsorption, wettability, diffusion, fracture and mechanical. several in vitro and in vivo methodologies are proposed for studying its mechanisms. however, mucoadhesion is not yet well understood. the aim of this study was to review the mechanisms and theories involved in mucoadhesion, as well as to describe the most-used methodologies and polymers in mucoadhesive drug delivery systems.
Thermoanalytical study of praziquantel-loaded PLGA nanoparticles
Mainardes, Rubiana Mara;Gremio, Maria Palmira Daflon;Evangelista, Raul Cesar;
Revista Brasileira de Ciências Farmacêuticas , 2006, DOI: 10.1590/S1516-93322006000400007
Abstract: polymeric nanoparticles have received great attention as potential controlled drug delivery systems. biodegradable polymers has been extensively used in the development of these drug carriers, and the polyesters such as polylactic acid, polyglycolic acid and their copolymers as poly-lactide-co-glycolide are the most used, considering its biocompatibility and biodegradability. thermal analysis techniques have been used for pharmaceutical substances for more than 30 years and are routine methods for screening drug-excipient interactions. the aim of this work is to use thermal analysis to characterize plga nanoparticles containing a hydrophobic drug, praziquantel. the results show that the drug is in an amorphous state or in disordered crystalline phase of molecular dispersion in the plga polymeric matrix and that the microencapsulation process did not interfere with the chemical structure of the polymer, mantaining the structural drug integrity.
Efeito da concentra??o do amido de milho na libera??o de paracetamol de comprimidos
Castro, Ana Dóris de;Vicente, Joice Alessandra;Mour?o, Samanta Cardozo;Bueno, José Hamilton Ferreira;Evangelista, Raul Cesar;Gremio, Maria Palmira Daflon;
Revista Brasileira de Ciências Farmacêuticas , 2003, DOI: 10.1590/S1516-93322003000300008
Abstract: this paper describes the influence of maize starch concentration on the physical characteristics and on in vitro release of acetaminophen from compressed tablets. the granulates were analyzed in relation to size distribution and bulk and compacted densities, and the tablets in relation to mean weight, thickness, hardness, friability and disintegration time. the tablets were prepared from granulates made by wet granulation with 10% starch paste in three formulations. although the tablets obtained have presented characteristics in accordance with pharmacopeial limits, the results indicate that variations on starch concentration cause differences on the several physical parameters studied. higher starch concentration probably originates an interaction among the ingredients of the formulations, interfering on the in vitro drug release.this fact demonstrates the importance in optimizing the concentration of the adjutants in a tablet formulation, because, although a short variation in this concentration has no significant effect on disintegration time, the amount of released drug can be substantially modified.
Reversed phase HPLC determination of zidovudine in rat plasma and its pharmacokinetics after a single intranasal dose administration
MAINARDES,RUBIANA M; PALMIRA D. GREMIO,MARIA;
Biological Research , 2009, DOI: 10.4067/S0716-97602009000300010
Abstract: the development and validation of a simple and accurate method based on hplc with ultraviolet detection for the quantification of zidovudine in rat plasma and its application to a pharmacokinetic study following a single intranasal dose zidovudine is described. zidovudine was extracted from the plasma using a single-step deproteinization. chromatographic separation of zidovudine from interfering components was achieved with a c-18 reverse phase column, a mobile phase consisting of a mixture of sodium acetate buffer (55mm) with ph adjusted to 7.0 and acetonitrile (91:9 v/v) and uv detection set at 265 nm. the method was linear from 100 to 10000 ng.ml"1 (r2 > 0.9995), and zidovudine had a mean recovery from plasma of 92.8%. the coefficient of variation of inter-day and intra-day quality control samples was less than 15%. after a single intranasal dose of zidovudine administered to rats, pharmacokinetic parameters (auc0 24, cmax, t , t1/2) were determined. the proposed method was found to be simple, specific, accurate, and precise and could be applied to the quantitative analysis of clinical pharmacokinetic studies of zidovudine in rats.
Reversed phase HPLC determination of zidovudine in rat plasma and its pharmacokinetics after a single intranasal dose administration
RUBIANA M MAINARDES,MARIA PALMIRA D. GREMIO
Biological Research , 2009,
Abstract: The development and validation of a simple and accurate method based on HPLC with ultraviolet detection for the quantification of zidovudine in rat plasma and its application to a pharmacokinetic study following a single intranasal dose zidovudine is described. Zidovudine was extracted from the plasma using a single-step deproteinization. Chromatographic separation of zidovudine from interfering components was achieved with a C-18 reverse phase column, a mobile phase consisting of a mixture of sodium acetate buffer (55mM) with pH adjusted to 7.0 and acetonitrile (91:9 v/v) and UV detection set at 265 nm. The method was linear from 100 to 10000 ng.mL"1 (r2 > 0.9995), and zidovudine had a mean recovery from plasma of 92.8%. The coefficient of variation of inter-day and intra-day quality control samples was less than 15%. After a single intranasal dose of zidovudine administered to rats, pharmacokinetic parameters (AUC0 24, Cmax, t , t1/2) were determined. The proposed method was found to be simple, specific, accurate, and precise and could be applied to the quantitative analysis of clinical pharmacokinetic studies of zidovudine in rats.
Development and validation of HPLC method for analysis of dexamethasone acetate in microemulsions
Urban, Maria Cristina Cocenza;Mainardes, Rubiana Mara;Gremio, Maria Palmira Daflon;
Brazilian Journal of Pharmaceutical Sciences , 2009, DOI: 10.1590/S1984-82502009000100010
Abstract: a simple, rapid, accurate and sensitive method was developed for quantitative analysis of dexamethasone acetate in microemulsions using high performance liquid chromatography (hplc) with uv detection. the chromatography parameters were stainless steel lichrospher 100 rp-18 column (250 mm x 4 mm i.d., 5 μm particle size), at 30 ± 2 oc. the isocratic mobile phase was methanol:water (65:35; v/v) at a flow rate of at 1.0 ml.min-1. the determinations were performed using uv-vis detector set at 239 nm. samples were prepared with methanol and the volume injected was 20 μl. the analytical curve was linear (r2 0.9995) over a wide concentration range (2.0-30.0 μg.ml-1). the presence of components of the microemulsion did not interfere in the results of the analysis. the method showed adequate precision, with a relative standard deviation (rsd) smaller than 3%. the accuracy was analyzed by adding a standard drug and good recovery values were obtained for all drug concentrations used. the hplc method developed in this study showed specificity and selectivity with linearity in the working range and good precision and accuracy, making it very suitable for quantification of dexamethasone in microemulsions. the analytical procedure is reliable and offers advantages in terms of speed and low cost of reagents.
Granulomatous Reactivation during the Course of a Leprosy Infection: Reaction or Relapse
Maria Angela Bianconcini Trindade ,Gil Benard,Somei Ura,Cássio Cesar Ghidella,Jo?o Carlos Regazzi Avelleira,Francisco Reis Vianna,Alfredo Bolchat Marques,Ben Naafs equal contributor,Raul Negr?o Fleury equal contributor
PLOS Neglected Tropical Diseases , 2010, DOI: 10.1371/journal.pntd.0000921
Abstract: Background Leprosy is a chronic granulomatous infectious disease and is still endemic in many parts of the world. It causes disabilities which are the consequence of nerve damage. This damage is in most cases the result of immunological reactions. Objectives To investigate the differences between a type 1 leprosy (reversal) reaction and relapse on using histopathology. Methods The histopathological changes in 167 biopsies from 66 leprosy patients were studied. The patients were selected when their sequential biopsies demonstrated either different patterns or maintained the same pattern of granulomatous reaction over more than two years during or after the treatment of leprosy. Results In 57 of the patients studied, a reactivation was seen which coincided with a decrease in the bacteriological index (BI), suggesting that this reactivation (reversal reaction or type 1 leprosy reaction) coincides with an effective capacity for bacteriological clearance. In nine patients, an increase of the bacteriologic index (IB) or persistence of solid bacilli occurred during the reactivation, indicating proliferative activity, suggestive of a relapse. The histopathological aspects of the granulomas were similar in both groups. Conclusion Bacterioscopy provided the only means to differentiate a reversal reaction from a relapse in patients with granulomatous reactivation. The type 1 leprosy reaction may be considered as a part effective immune reconstitution (reversal, upgrading reaction) or as a mere hypersensitivity reaction (downgrading reaction) in a relapse.
Unbiased diffusion of Brownian particles on disordered correlated potentials
Raul Salgado-Garcia,Cesar Maldonado
Physics , 2015,
Abstract: In this work we study the diffusion of non-interacting overdamped particles, moving on unbiased disordered correlated potentials, subjected to Gaussian white noise. We obtain an exact expression for the diffusion coefficient which allows us to prove that the unbiased diffusion of overdamped particles on a random polymer does not depend on the correlations of the disordered potentials. This universal behavior of the unbiased diffusivity is a direct consequence of the validity of the Einstein relation and the decay of correlations of the random polymer. We test the independence on correlations of the diffusion coefficient for correlated polymers produced by two different stochastic processes, a one-step Markov chain and the expansion-modification system. Within the accuracy of our simulations, we found that the numerically obtained diffusion coefficient for these systems agree with the analytically calculated ones, confirming our predictions.
Markov Approximations of Gibbs measures for long-range potentials on 1D lattices
Cesar Maldonado,Raul Salgado-Garcia
Physics , 2013, DOI: 10.1088/1742-5468/2013/08/P08012
Abstract: We study one-dimensional lattice systems with pair-wise interactions of in?nite range. We show projective convergence of Markov measures to the unique equilibrium state. For this purpose we impose a slightly stronger condition than summability of variations on the regularity of the interaction. With our condition we are able to explicitly obtain stretched exponential bounds for the rate of mixing of the equilibrium state. Finally we show convergence for the entropy of the Markov measures to that of the equilibrium state via the convergence of their topological pressure.
Concep??o de roubo em pré-escolares
Martins, Raul Arag?o;
Educa??o & Sociedade , 1997, DOI: 10.1590/S0101-73301997000200007
Abstract: from the pioneering work of j. piaget "the moral judgment of the child" we have reviewed the contributions to this study of childrens' conception of stealing . using a story about a minor theft, we examined how kindergarten children answer questions about the right and wrong of stealing and now they justified their answers. in addition we examined childrens' perception of the existence, contingence and relativity of rules. we examined 80 children from a public and a private school, each divided in two groups. the results have shown that children have a notion of stealing as a wrong act and to justify these answers they show five patterns of justifications, as well as judgment of intentionality. results were discussed in terms of piaget's moral development theory.
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