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Search Results: 1 - 10 of 5044 matches for " Borges VRA "
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Nanoemulsion containing dapsone for topical administration: a study of in vitro release and epidermal permeation
Borges VRA,Simon A,Sena ARC,Cabral LM
International Journal of Nanomedicine , 2013,
Abstract: Vinícius Raphael de Almeida Borges, Alice Simon, Adrian Ricardo Cuello Sena, Lúcio Mendes Cabral, Valéria Pereira de Sousa Department of Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Background: Topical administration of dapsone can be an alternative route for treatment of leprosy and can also provide new therapeutic applications for an established drug. However, the physicochemical properties of dapsone make it difficult to incorporate into conventional formulations. The current study was directed toward developing a stable nanoemulsion that contains dapsone which can be adapted for topical use. Methods: Nanoemulsions were prepared using isopropyl myristate or n-methyl-pyrrolidone as the oil phase, and characterized according to their mean droplet size, conductivity, refractive index, pH, drug content, and stability. The in vitro release of dapsone and its ability to permeate the epidermis were also evaluated. Results: Physicochemical characterization demonstrated that nanosystems were formed, which had a uniform droplet distribution and a pH compatible with the skin surface. Use of n-methyl-pyrrolidone provided a greater nanoemulsion region and higher solubilization of dapsone, and increased the in vitro release rate when compared with a nanoemulsion prepared using isopropyl myristate. However, use of isopropyl myristate promoted an increase in in vitro epidermal permeation that followed the Higuchi model. This demonstrates the ability of a nanosystem to influence permeation of dapsone through the skin barrier. Furthermore, the nanoemulsions developed and evaluated here had ideal physicochemical stability over a 3-month period. Conclusion: Incorporation of dapsone into a nanoemulsion may be a promising system for enabling topical delivery of dapsone, while minimizing skin permeation, for the treatment of acne. The method developed here used isopropyl myristate as the oil phase, and promoted permeation of dapsone through the skin barrier for the treatment of leprosy upon use of n-methyl-pyrrolidone as the oil phase. Keywords: dapsone, nanoemulsion, topical, release, permeation
Preparation and evaluation of lidocaine hydrochloride in cyclodextrin inclusion complexes for development of stable gel in association with chlorhexidine gluconate for urogenital use
Soares da Silva LFJ,Carmo FA,Borges VRA,Monteiro LM
International Journal of Nanomedicine , 2011,
Abstract: Luiz Francisco Jones Soares da Silva, Flavia Almada do Carmo, Vinicius Raphael de Almeida Borges, Lidiane Mota Monteiro, Carlos Rangel Rodrigues, Lúcio Mendes Cabral, Valeria Pereira de SousaDepartamento de Medicamentos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BrazilAbstract: Inclusions of lidocaine hydrochloride in cyclodextrins were prepared to obtain stable complexes compatible for association with chlorhexidine in a new gel formulation for use in urogenital applications. Two cyclodextrins, β-cyclodextrin and methyl-β-cyclodextrin, were used for encapsulating lidocaine hydrochloride through solubilization and kneading techniques. The lidocaine–cyclodextrin complexes were characterized by ultraviolet spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. The results revealed that the techniques generated good yields of inclusion products that maintained the functional properties of lidocaine. In addition, the inclusion products obtained improved the compatibility of lidocaine hydrochloride with chlorhexidine in solution and a gel formulation. The gel formulation displayed desirable rheological and physicochemical properties. The results presented here are the first description of the inclusion of lidocaine with cyclodextrins, which improves compatibility with chlorhexidine in formulations for simultaneous delivery.Keywords: solubilization and kneading inclusion techniques, cyclodextrins, lidocaine hydrochloride, chlorhexidine gluconate incompatibility, urogenital gel formulations
Preparation and evaluation of lidocaine hydrochloride in cyclodextrin inclusion complexes for development of stable gel in association with chlorhexidine gluconate for urogenital use
Soares da Silva LFJ, Carmo FA, Borges VRA, Monteiro LM, Rodrigues CR, Cabral LM, Sousa VP
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S20409
Abstract: eparation and evaluation of lidocaine hydrochloride in cyclodextrin inclusion complexes for development of stable gel in association with chlorhexidine gluconate for urogenital use Original Research (4959) Total Article Views Authors: Soares da Silva LFJ, Carmo FA, Borges VRA, Monteiro LM, Rodrigues CR, Cabral LM, Sousa VP Published Date June 2011 Volume 2011:6 Pages 1143 - 1154 DOI: http://dx.doi.org/10.2147/IJN.S20409 Luiz Francisco Jones Soares da Silva, Flavia Almada do Carmo, Vinicius Raphael de Almeida Borges, Lidiane Mota Monteiro, Carlos Rangel Rodrigues, Lúcio Mendes Cabral, Valeria Pereira de Sousa Departamento de Medicamentos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil Abstract: Inclusions of lidocaine hydrochloride in cyclodextrins were prepared to obtain stable complexes compatible for association with chlorhexidine in a new gel formulation for use in urogenital applications. Two cyclodextrins, β-cyclodextrin and methyl-β-cyclodextrin, were used for encapsulating lidocaine hydrochloride through solubilization and kneading techniques. The lidocaine–cyclodextrin complexes were characterized by ultraviolet spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. The results revealed that the techniques generated good yields of inclusion products that maintained the functional properties of lidocaine. In addition, the inclusion products obtained improved the compatibility of lidocaine hydrochloride with chlorhexidine in solution and a gel formulation. The gel formulation displayed desirable rheological and physicochemical properties. The results presented here are the first description of the inclusion of lidocaine with cyclodextrins, which improves compatibility with chlorhexidine in formulations for simultaneous delivery.
Nanoemulsion containing dapsone for topical administration: a study of in vitro release and epidermal permeation
Borges VRA, Simon A, Sena ARC, Cabral LM, de Sousa VP
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S39383
Abstract: noemulsion containing dapsone for topical administration: a study of in vitro release and epidermal permeation Original Research (776) Total Article Views Authors: Borges VRA, Simon A, Sena ARC, Cabral LM, de Sousa VP Published Date February 2013 Volume 2013:8 Pages 535 - 544 DOI: http://dx.doi.org/10.2147/IJN.S39383 Received: 20 October 2012 Accepted: 06 December 2012 Published: 11 February 2013 Vinícius Raphael de Almeida Borges, Alice Simon, Adrian Ricardo Cuello Sena, Lúcio Mendes Cabral, Valéria Pereira de Sousa Department of Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Background: Topical administration of dapsone can be an alternative route for treatment of leprosy and can also provide new therapeutic applications for an established drug. However, the physicochemical properties of dapsone make it difficult to incorporate into conventional formulations. The current study was directed toward developing a stable nanoemulsion that contains dapsone which can be adapted for topical use. Methods: Nanoemulsions were prepared using isopropyl myristate or n-methyl-pyrrolidone as the oil phase, and characterized according to their mean droplet size, conductivity, refractive index, pH, drug content, and stability. The in vitro release of dapsone and its ability to permeate the epidermis were also evaluated. Results: Physicochemical characterization demonstrated that nanosystems were formed, which had a uniform droplet distribution and a pH compatible with the skin surface. Use of n-methyl-pyrrolidone provided a greater nanoemulsion region and higher solubilization of dapsone, and increased the in vitro release rate when compared with a nanoemulsion prepared using isopropyl myristate. However, use of isopropyl myristate promoted an increase in in vitro epidermal permeation that followed the Higuchi model. This demonstrates the ability of a nanosystem to influence permeation of dapsone through the skin barrier. Furthermore, the nanoemulsions developed and evaluated here had ideal physicochemical stability over a 3-month period. Conclusion: Incorporation of dapsone into a nanoemulsion may be a promising system for enabling topical delivery of dapsone, while minimizing skin permeation, for the treatment of acne. The method developed here used isopropyl myristate as the oil phase, and promoted permeation of dapsone through the skin barrier for the treatment of leprosy upon use of n-methyl-pyrrolidone as the oil phase.
Age as a Problematic and Problematized Issue of Criminal Responsibility
Martin Vávra
Central European Journal of Public Policy , 2012,
Abstract: The article deals with young people as they are depicted in discussions on "youth delinquency" and "juvenile justice". I focus on the political discourse (as represented by debates taking place within the Parliament in 1930–2009) and the expert discourse (as represented by academic texts on the subject from the same time period). I tried to solve one paradox which motivated my research: Why was the time period of relative toughening of penal policy when, according to public opinion polls, a substantial majority of Czech adults favoured the decreasing of the minimum age of criminal responsibility and such an amendment was actually repeatedly proposed in the legislature, marked by consistent victories of the approach to juvenile persons which prefers care, education and therapy instead of punishment?
A New Possible Way to Explain the DAMA Results
J. Va'vra
Physics , 2014, DOI: 10.1016/j.physletb.2014.06.038
Abstract: At present there is an e?ort to reconcile the results of the DAMA experiment with those from other Dark Matter experiments such as CoGeNT, CRESST, CDMS, and all LXe experiments. The author suggests a new model describing the Dark Matter signal as the result of collisions of very light (1-to-few GeV/c^2) WIMPs with hydrogen, and compares it with currently accepted models of collisions with heavy nuclei (Na, Ge or Xe). The hydrogen target would come from H-contamination of NaI(Tl), Ge and CaWO4 crystals. Initial tuning indicates that one can explain the modulation amplitude of DAMA and CoGeNT with this model, assuming a WIMP-proton cross section between 10^33 and 10^32 cm^2. This paper should be considered to be a new idea which will need substantial new experimental input from all involved experiments.
What is needed to accept the new explanation of DAMA results
J. Va'vra
Physics , 2014,
Abstract: The DAMA experiment clearly observes a small oscillatory signal. The observed yearly modulation is in phase with the Earth's motion around the Sun. Recent reference [Vavra, 2014] suggested that the DAMA experiment observes a WIMP of much smaller mass than what Xenon 10, Xenon 100, LUX and CDMS experiments can possibly reach. Scattering would occur on proton or oxygen target present in the NaI(Tl) crystal as OH-contamination at a few ppm level. This paper elaborates further on the idea that the OH-molecule could act as a very sensitive detection mechanism for neutrons or WIMPs, and suggests a calibration procedure to prove this idea. We also propose a new detector concept to detect a low mass WIMP.
Molecular excitations: a new way to detect Dark matter
J. Va'vra
Physics , 2014, DOI: 10.1016/j.physletb.2014.07.023
Abstract: We believe that the Dark Matter (DM) search should be expanded into the domain of detectors sensitive to molecular excitations, and so that we should create detectors which are more sensitive to collisions with very light WIMPs. In this paper we investigate in detail di-atomic molecules, such as Fused Silica material with large OH-molecule content, and water molecules. Presently, we do not have suitable low cost IR detectors to observe single photons, however some OH-molecular excitations extend to visible and UV wavelengths, and can be measured by Bialkali photocathodes. There are many other chemical substances with di-atomic molecules, or more complex oil molecules, which could be investigated also. This idea invites searches in experiments having large target volumes of such materials coupled to a large array of single-photon detectors with Bialkali or infrared-sensitive photocathodes.
A new way to explain the 511keV signal from the center of the Galaxy and some dark matter experiments
J. Va'vra
Physics , 2013,
Abstract: The first gamma-ray line originating from outside the solar system that was ever detected is the 511keV emission from the center of our Galaxy. The accepted explanation of this signal is the annihilation of electrons and positrons. However, despite 30 years of intense theoretical and observational investigation, the main sources of positrons have not been identified up to now. In this paper we propose an alternative explanation: the observed signal is due to atomic transitions to small hydrogen atom, where electron is captured by proton on a small tight orbit around proton. This model may also be relevant to some dark matter searching experiments capable of observing a very small signal. We propose a detector to improve their detection-reach even further down to smaller signals equivalent to a single electron and a single photon of a few eV energy. We describe the status of the experimental search to find the small hydrogen atom, and propose a method how to discover it in the lab directly. Key words: 511keV peak at the galactic center, small hydrogen atom, DDL atom, low mass WIMPs interacting with electron shell, dark matter search experiments
On the Finiteness property of negative cubic Pisot bases
Tomá? Vávra
Mathematics , 2014,
Abstract: We study arithmetical aspects of Ito-Sadahiro number systems with negative base. We show that the bases $-\beta<-1$, where $\beta$ is zero of $x^3-mx^2-mx-m,\ m\in\mathbb N,$ possess the so-called finiteness property. For the Tribonacci base $-\gamma,$ zero of $x^3-x^2-x-1$, we present an effective algorithm for addition and subtraction. In particular, we present a finite state transducer performing these operations. As a consequence of the structure of the transducer, we determine the maximal number of fractional digits arising from addition or subtraction of two $(-\gamma)$-integers.
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