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Marcos Luciano Bruschi - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the methylene blue addition in binary polymeric systems composed by poloxamer 407 and carbopol 934p using quality by design rheological textural and mucoadhesive analysis
Drug Development and Industrial Pharmacy, 2016Co-Authors: Mariana Volpato Junqueira, Fernanda Belincanta Borghipangoni, Sabrina Barbosa De Souza Ferreira, Marcos Luciano BruschiAbstract:AbstractThis study describes the investigation about the physicochemical behavior of methylene blue (Mb) addition to systems containing poloxamer 407 (Polox), Carbopol 934P (Carb), intended to be locally used by photodynamic therapy. A factorial design 23 (plus center point) was used to analyze the rheological, mucoadhesive and textural properties of the preparations. Systems containing the lower concentrations of Polox (15 and 17.5%, w/w) exhibited pseudoplastic flow and low degrees of Rheopexy. On the other hand, at higher Polox concentration (20%, w/w) the systems display plastic flow and thixotropy. Carb and Mb exhibited a negative influence for the consistency and flow behavior index, due to the interaction between them. For most of the formulations, the increase of Polox and Mb content significantly increased storage modulus, loss modulus and dynamic viscosity. The systems display a sol–gel transition temperature, existing as a liquid at room temperature and gel at 29–37 °C. Increasing the temperatu...
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Evaluation of the methylene blue addition in binary polymeric systems composed by poloxamer 407 and Carbopol 934P using quality by design: rheological, textural, and mucoadhesive analysis
2016Co-Authors: Mariana Volpato Junqueira, Sabrina Barbosa De Souza Ferreira, Fernanda Belincanta Borghi-pangoni, Marcos Luciano BruschiAbstract:This study describes the investigation about the physicochemical behavior of methylene blue (Mb) addition to systems containing poloxamer 407 (Polox), Carbopol 934P (Carb), intended to be locally used by photodynamic therapy. A factorial design 23 (plus center point) was used to analyze the rheological, mucoadhesive and textural properties of the preparations. Systems containing the lower concentrations of Polox (15 and 17.5%, w/w) exhibited pseudoplastic flow and low degrees of Rheopexy. On the other hand, at higher Polox concentration (20%, w/w) the systems display plastic flow and thixotropy. Carb and Mb exhibited a negative influence for the consistency and flow behavior index, due to the interaction between them. For most of the formulations, the increase of Polox and Mb content significantly increased storage modulus, loss modulus and dynamic viscosity. The systems display a sol–gel transition temperature, existing as a liquid at room temperature and gel at 29–37 °C. Increasing the temperature and the polymer concentration, the compressional properties of systems significantly increased. The mucoadhesion was noted to all formulations, except to systems composed by 15% (w/w) of Polox. The analyses enabled to understand and predict the performance of formulations and the polymer–Mb interactions, tailoring to the suit systems (Polox/Carb/Mb): 17.5/0.50/0.20 and 20/0.15/0.25.
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Development and characterisation of semisolid systems to deliver propolis in the oral cavity
Universidade Estadual Paulista, 2010Co-Authors: Adriana Nakahara Hirata, Marcos Luciano BruschiAbstract:Pharmaceutical formulations containing poloxamer 407 (P407), Carbopol 934P (C934P) or gelatin (GELA), with ethanolic propolis extract (PE), were designed for the treatment of oral mucosal diseases. PE was produced and its quality was assessed by measuring its specific gravity, pH, weight of dry residue and total flavonoid content. Monopolymeric and binary polymeric formulations were prepared and their gelling temperature (Tsol/gel), pH, continuous flow rheology and mucoadhesion were studied. PE exhibited good quality and the formulations were easy to prepare and showed a wide range of consistency. Most of the formulations showed thermoresponsive behaviour and only those containing 15% P407, plus 0.20% C934P or 1.0 % GELA, displayed Tsol/gel suitable for application to the oral mucosa. Monopolymeric formulations, containing C934P or GELA, and binary formulations exhibited pseudoplastic flow and low degrees of thixotropy. Monopolymeric formulations containing P407 exhibited pseudoplastic flow and Rheopexy. The mucoadhesive properties of the systems could not be assessed. Fragments of formulation were found to remain stuck to parts of the mucin disc, owing to cohesive failure of the samples and of the sample/mucin interface. The data obtained on these formulations indicate a potentially useful role in the treatment of oral mucosal diseases. Keywords: Propolis. Mucoadhesion. Poloxamer 407. Carbopol 934P. Gelatin. RESUMO Desenvolvimento e caracterização de sistemas semi-sólidos para liberação de própolis na cavidade bucal Formulações farmacêuticas contendo poloxamer 407 (P407), Carbopol 934P (C934P) ou gelatina (GELA), e extrato de própolis (EP) foram desenvolvidos para o tratamento de doenças da mucosa oral. EP foi produzido e sua qualidade foi avaliada quanto ao resíduo seco e ao teor de flavonóides totais. Formulações monopoliméricas e poliméricas binárias foram produzidas e a temperatura de gelificação (Tsol/gel), o pH, a reologia, assim como a mucoadesão das mesmas foram avaliados. O EP apresentou boa qualidade, as preparações foram fáceis de produzir e apresentaram uma ampla variação de consistência. A maioria das preparações apresentou comportamento de resposta térmica e apenas as formulações contendo 15% P407 e 0,20% C934P ou 1,0% GELA apresentaram Tsol/gel adequada para a administração na mucosa oral. Formulações monopoliméricas, contendo C934P ou GELA, e binárias exibiram comportamento de fluxo pseudoplástico e baixo grau de tixotropia. Formulações monopoliméricas de P407 exibiram fluxo pseudoplástico e reopexia. As propriedades mucoadesivas dos sistemas não puderam ser avaliadas. Fragmentos de formulações foram encontrados aderidos em alguns lugares do disco de mucina devido à falha de coesão das amostras e da interface amostra/mucina. Os resultados obtidos com essas formulações indicam a utilidade das mesmas no tratamento de doenças da mucosa oral. Palavras-chave: Própolis. Mucoadesão. Poloxamer 407. Carbopol 934P. Gelatina
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<b>Development and characterisation of semisolid systems to deliver propolis in the oral cavity</b>
Universidade Estadual Paulista, 2010Co-Authors: Adriana Nakahara Hirata, Marcos Luciano BruschiAbstract:Pharmaceutical formulations containing poloxamer 407 (P407), Carbopol 934P (C934P) or gelatin (GELA), with ethanolic propolis extract (PE), were designed for the treatment of oral mucosal diseases. PE was produced and its quality was assessed by measuring its specific gravity, pH, weight of dry residue and total flavonoid content. Monopolymeric and binary polymeric formulations were prepared and their gelling temperature (Tsol/gel), pH, continuous flow rheology and mucoadhesion were studied. PE exhibited good quality and the formulations were easy to prepare and showed a wide range of consistency. Most of the formulations showed thermoresponsive behaviour and only those containing 15% P407, plus 0.20% C934P or 1.0 % GELA, displayed Tsol/gel suitable for application to the oral mucosa. Monopolymeric formulations, containing C934P or GELA, and binary formulations exhibited pseudoplastic flow and low degrees of thixotropy. Monopolymeric formulations containing P407 exhibited pseudoplastic flow and Rheopexy. The mucoadhesive properties of the systems could not be assessed. Fragments of formulation were found to remain stuck to parts of the mucin disc, owing to cohesive failure of the samples and of the sample/mucin interface. The data obtained on these formulations indicate a potentially useful role in the treatment of oral mucosal diseases. <i>Keywords</i>: Propolis. Mucoadhesion. Poloxamer 407. Carbopol 934P. Gelatin. <b>RESUMO</b> <i>Desenvolvimento e caracterização de sistemas semi-sólidos para liberação de própolis na cavidade bucal</i> Formulações farmacêuticas contendo poloxamer 407 (P407), Carbopol 934P (C934P) ou gelatina (GELA), e extrato de própolis (EP) foram desenvolvidos para o tratamento de doenças da mucosa oral. EP foi produzido e sua qualidade foi avaliada quanto ao resíduo seco e ao teor de flavonóides totais. Formulações monopoliméricas e poliméricas binárias foram produzidas e a temperatura de gelificação (Tsol/gel), o pH, a reologia, assim como a mucoadesão das mesmas foram avaliados. O EP apresentou boa qualidade, as preparações foram fáceis de produzir e apresentaram uma ampla variação de consistência. A maioria das preparações apresentou comportamento de resposta térmica e apenas as formulações contendo 15% P407 e 0,20% C934P ou 1,0% GELA apresentaram Tsol/gel adequada para a administração na mucosa oral. Formulações monopoliméricas, contendo C934P ou GELA, e binárias exibiram comportamento de fluxo pseudoplástico e baixo grau de tixotropia. Formulações monopoliméricas de P407 exibiram fluxo pseudoplástico e reopexia. As propriedades mucoadesivas dos sistemas não puderam ser avaliadas. Fragmentos de formulações foram encontrados aderidos em alguns lugares do disco de mucina devido à falha de coesão das amostras e da interface amostra/mucina. Os resultados obtidos com essas formulações indicam a utilidade das mesmas no tratamento de doenças da mucosa oral. <i>Palavras-chave</i>: Própolis. Mucoadesão. Poloxamer 407. Carbopol 934P. Gelatina
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semisolid systems containing propolis for the treatment of periodontal disease in vitro release kinetics syringeability rheological textural and mucoadhesive properties
Journal of Pharmaceutical Sciences, 2007Co-Authors: Marcos Luciano Bruschi, David S Jones, Heitor Panzeri, Maria Palmira Daflon Gremiao, Osvaldo De Freitas, Elza Helena Guimaraes LaraAbstract:ABSTRACT Formulations containing poloxamer 407 (P407), carbopol 934P (C934P), and propolis extract (PE) were designed for the treatment of periodontal disease. Gelation temperature, in vitro drug release, rheology, hardness, compressibility, adhesiveness, mucoadhesion, and syringeability of formulations were determined. Propolis release from formulations was controlled by the phenomenon of relaxation of polymer chains. Formulations exhibited pseudoplastic flow and low degrees of thixotropy or Rheopexy. In most samples, increasing the concentration of C934P content significantly increased storage modulus ( G ′), loss modulus ( G ″), and dynamic viscosity ( η ′), at 5°C, G ″ exceeded G ′. At 25 and 37°C, η ′ of each formulation depended on the oscillatory frequency. Formulations showed thermoresponsive behavior, existing as a liquid at room temperature and gel at 34–37°C. Increasing the C934P content or temperature significantly increased formulation hardness, compressibility, and adhesiveness. The greatest mucoadhesion was noted in the formulation containing 15% P407 (w/w) and 0.25% C934P (w/w). The work of syringeability values of all formulations were similar and very desirable with regard to ease of administration. The data obtained in these formulations indicate a potentially useful role in the treatment of periodontitis and suggest they are worthy of clinical evaluation. © 2007 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 96:2074–2089, 2007
Dilson E. Rassier - One of the best experts on this subject based on the ideXlab platform.
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Thixotropy and Rheopexy of muscle fibers probed using sinusoidal oscillations.
PLOS ONE, 2015Co-Authors: David Altman, Fabio C. Minozzo, Dilson E. RassierAbstract:Length changes of muscle fibers have previously been shown to result in a temporary reduction in fiber stiffness that is referred to as thixotropy. Understanding the mechanism of this thixotropy is important to our understanding of muscle function since there are many instances in which muscle is subjected to repeated patterns of lengthening and shortening. By applying sinusoidal length changes to one end of single permeabilized muscle fibers and measuring the force response at the opposite end, we studied the history-dependent stiffness of both relaxed and activated muscle fibers. For length change oscillations greater than 1 Hz, we observed thixotropic behavior of activated fibers. Treatment of these fibers with EDTA and blebbistatin, which inhibits myosin-actin interactions, quashed this effect, suggesting that the mechanism of muscle fiber thixotropy is cross-bridge dependent. We modeled a half-sarcomere experiencing sinusoidal length changes, and our simulations suggest that thixotropy could arise from force-dependent cross-bridge kinetics. Surprisingly, we also observed that, for length change oscillations less than 1 Hz, the muscle fiber exhibited Rheopexy. In other words, the stiffness of the fiber increased in response to the length changes. Blebbistatin and EDTA did not disrupt the rheopectic behavior, suggesting that a non-cross-bridge mechanism contributes to this phenomenon.
David Altman - One of the best experts on this subject based on the ideXlab platform.
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Thixotropy and Rheopexy of muscle fibers probed using sinusoidal oscillations.
PLOS ONE, 2015Co-Authors: David Altman, Fabio C. Minozzo, Dilson E. RassierAbstract:Length changes of muscle fibers have previously been shown to result in a temporary reduction in fiber stiffness that is referred to as thixotropy. Understanding the mechanism of this thixotropy is important to our understanding of muscle function since there are many instances in which muscle is subjected to repeated patterns of lengthening and shortening. By applying sinusoidal length changes to one end of single permeabilized muscle fibers and measuring the force response at the opposite end, we studied the history-dependent stiffness of both relaxed and activated muscle fibers. For length change oscillations greater than 1 Hz, we observed thixotropic behavior of activated fibers. Treatment of these fibers with EDTA and blebbistatin, which inhibits myosin-actin interactions, quashed this effect, suggesting that the mechanism of muscle fiber thixotropy is cross-bridge dependent. We modeled a half-sarcomere experiencing sinusoidal length changes, and our simulations suggest that thixotropy could arise from force-dependent cross-bridge kinetics. Surprisingly, we also observed that, for length change oscillations less than 1 Hz, the muscle fiber exhibited Rheopexy. In other words, the stiffness of the fiber increased in response to the length changes. Blebbistatin and EDTA did not disrupt the rheopectic behavior, suggesting that a non-cross-bridge mechanism contributes to this phenomenon.
Mariana Volpato Junqueira - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the methylene blue addition in binary polymeric systems composed by poloxamer 407 and carbopol 934p using quality by design rheological textural and mucoadhesive analysis
Drug Development and Industrial Pharmacy, 2016Co-Authors: Mariana Volpato Junqueira, Fernanda Belincanta Borghipangoni, Sabrina Barbosa De Souza Ferreira, Marcos Luciano BruschiAbstract:AbstractThis study describes the investigation about the physicochemical behavior of methylene blue (Mb) addition to systems containing poloxamer 407 (Polox), Carbopol 934P (Carb), intended to be locally used by photodynamic therapy. A factorial design 23 (plus center point) was used to analyze the rheological, mucoadhesive and textural properties of the preparations. Systems containing the lower concentrations of Polox (15 and 17.5%, w/w) exhibited pseudoplastic flow and low degrees of Rheopexy. On the other hand, at higher Polox concentration (20%, w/w) the systems display plastic flow and thixotropy. Carb and Mb exhibited a negative influence for the consistency and flow behavior index, due to the interaction between them. For most of the formulations, the increase of Polox and Mb content significantly increased storage modulus, loss modulus and dynamic viscosity. The systems display a sol–gel transition temperature, existing as a liquid at room temperature and gel at 29–37 °C. Increasing the temperatu...
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Evaluation of the methylene blue addition in binary polymeric systems composed by poloxamer 407 and Carbopol 934P using quality by design: rheological, textural, and mucoadhesive analysis
2016Co-Authors: Mariana Volpato Junqueira, Sabrina Barbosa De Souza Ferreira, Fernanda Belincanta Borghi-pangoni, Marcos Luciano BruschiAbstract:This study describes the investigation about the physicochemical behavior of methylene blue (Mb) addition to systems containing poloxamer 407 (Polox), Carbopol 934P (Carb), intended to be locally used by photodynamic therapy. A factorial design 23 (plus center point) was used to analyze the rheological, mucoadhesive and textural properties of the preparations. Systems containing the lower concentrations of Polox (15 and 17.5%, w/w) exhibited pseudoplastic flow and low degrees of Rheopexy. On the other hand, at higher Polox concentration (20%, w/w) the systems display plastic flow and thixotropy. Carb and Mb exhibited a negative influence for the consistency and flow behavior index, due to the interaction between them. For most of the formulations, the increase of Polox and Mb content significantly increased storage modulus, loss modulus and dynamic viscosity. The systems display a sol–gel transition temperature, existing as a liquid at room temperature and gel at 29–37 °C. Increasing the temperature and the polymer concentration, the compressional properties of systems significantly increased. The mucoadhesion was noted to all formulations, except to systems composed by 15% (w/w) of Polox. The analyses enabled to understand and predict the performance of formulations and the polymer–Mb interactions, tailoring to the suit systems (Polox/Carb/Mb): 17.5/0.50/0.20 and 20/0.15/0.25.
O Manero - One of the best experts on this subject based on the ideXlab platform.
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understanding thixotropic and antithixotropic behavior of viscoelastic micellar solutions and liquid crystalline dispersions i the model
Journal of Non-newtonian Fluid Mechanics, 1999Co-Authors: F Bautista, J M De Santos, J E Puig, O ManeroAbstract:Abstract A simple model consisting of the Upper Convected Maxwell constitutive equation and a kinetic equation for destruction and construction of structure, first proposed by Fredrickson in 1970, is used here to reproduce the complex rheological behavior of viscoelastic systems that also exhibit thixotropy and Rheopexy under shear flow. The model requires five parameters that have physical significance and that can be estimated from rheological measurements. Several steady and unsteady flow situations were analyzed with the model. The model predicts creep behavior, stress relaxation and the presence of thixotropic loops when the sample is subjected to transient stress cycles. Such behavior has been observed with surfactant-based solutions and dispersions. The role of the characteristic time for structure built up, λ, in the extent and shape of the thixotropic loops is demonstrated.
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note thixotropic antithixotropic behavior of surfactant based lamellar liquid crystals under shear flows
Journal of Rheology, 1995Co-Authors: J F A Soltero, J E Puig, O Roblesvasquez, O ManeroAbstract:Complex materials such as liquid crystals present complicated rheological responses when they are subjected to shear flows [Oswald and Allain (1988); Matsumoto et al. (1989); Paasch et al. (1989)]. In particular, AOT–water lamellar liquid crystals behave as weak gels when they are subjected to oscillatory shear [Robles‐Vazquez et al. (1993),(1994)] but when the applied stress surpasses the yield stress, they exhibit viscoelasticity [Soltero (1994)]. Also, for AOT–water biphasic dispersions at concentrations below the phase inversion concentration (≊8 wt % AOT) [Alexopoulos et al. (1989)], the formation of shear‐induced microstructures at high shear rates causes shear thickening [Valdes et al. (1993)]. Upon decreasing shear rates, the dispersion still preserves much of its structure and consequently its viscosity remains higher than the values measured in the increasing shear rate mode. This behavior is referred as Rheopexy or antithixotropy [Mewis (1979)]. Here we examine in detail the rheological response of lamellar liquid crystals under shear flows using a controlled‐stress rheometer. We consider two double tail surfactants, one anionic (AOT) and another cationic (DDAB), whose phase diagrams have been studied extensively [Fontell (1973); Franses and Hart (1983); Fontell et al. (1986)]. Particular attention is given to the hysteresis detected when the samples are sheared under increasing–decreasing shear stress modes which result in thixotropic and antithixotropic behavior.