Effect of sulfonated block copolymer on the equilibrium and thermal properties of sulfonated fluoroblock copolymer blend membrane / Efecto del copolímero en bloque sulfonado sobre las propiedades térmicas y de equilibrio de una membrana sulfonada mezclada con un fluoropolímero en bloque

Polymeric membrane technologies demand the synthesis of new polymers to enhance their equilibrium, thermal, and transport properties. Therefore, the focus of this investigation was the evaluation of the equilibrium and thermal properties of a sulfonated fluoroblock copolymer blend membrane composed of sulfonated poly(styre-ne-isobutylene-styrene) (SIBS SO3H) and a novel sulfonated fluoroblock copolymer composed of poly(4-fluo-rostyrene) (P4FS), poly(styrene) (PS) and poly(isobutylene) (PIB). The fluoroblock copolymer was synthesized using Atom Transfer Radical Polymerization (ATRP) and cationic polymerization. First, the molecular weight and the thermal stability of the block copolymer were determined using Gel Permeation Chromatography (GPC) and Thermogravimetric Analysis (TGA). Second, the chemical composition was monitored utilizing Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The molecular weight of P4FS-b-PS was Mn ~ 36,100; this value increased 8% after the cationic polymerization. The equilibrium properties of the membrane were evaluated using the water uptake and Ion-Exchange Capacity. The degradation behavior and the thermal transitions were determined using TGA and Differential Scanning Calorimetry (DSC), respectively. This newly membrane exhibited water uptake higher than 608% related to the improvement of 36% in the ion-exchange capacity and the increment of 25.31% and 25.24% in the energy required to produce the thermal transitions induced by the addition of the sulfonated fluoroblock copolymer.

La tecnología de membranas poliméricas requiere de la síntesis de nuevos polímeros que mejoren sus propiedades de equilibrio, térmicas y de transporte. Esta investigación tuvo como objetivo determinar las pro-piedades de equilibrio y térmicas de una membrana compuesta de poli(estireno-isobutileno-estireno) sulfonado (SIBS SO3H) y un fluoropolímero en bloque sulfonado compuesto de poli(4-fluorostireno) (P4FS), poli(estireno) (PS) y poli(isobutileno) (PIB). El fluoropolímero en bloque se sintetizó utilizando la técnica de polimerización radical por transferencia atómica (ATRP por sus siglas en inglés) y polimerización catiónica. El peso molecular y la estabilidad térmica del fluoropolímero en bloque fueron determinadas por medio de Cromatografía de Permeación en Gel (GPC) y un análisis termogravimétrico (TGA). La composición química se monitorizó utilizando espectroscopía infrarroja por transformada de Fourier (FTIR) y espectroscopía de Resonancia Magnética Nuclear (RMN). El peso molecular de P4FS-b-PS fue Mn ~ 36,100; este valor aumentó un 8% después de la polimerización catiónica. Las propiedades de equilibrio de la membrana fueron evaluadas por medio de la absorción de agua y la capacidad de intercambio iónico. El comportamiento de degradación y las transiciones térmicas se determinaron utilizando TGA y Calorimetría Diferencial de Barrido (DSC). Esta nueva membrana exhibió una absorción de agua mayor del 608% relacionada con la mejora del 36% en la capacidad de intercambio iónico y el incremento en 25.31% y 25.24% en la energía requerida para producir las transiciones termales inducidas por la adición del fluoropolímero sulfonado en bloque.

Segurança e eficácia dos stents farmacológicos eluidores de biolimus com polímero biodegradável: análise do registro EINSTEIN (Evaluation of Next-generation drug-eluting STEnt IN patients with coronary artery disease) / Safety and efficacy of biolimus-eluting stent with biodegradable polymer: insights from EINSTEIN (Evaluation of Next-generation drug-eluting STEnt IN patients with coronary artery disease) Registry

OBJETIVO: Avaliar a incidência de eventos adversos cardíacos maiores (morte cardíaca, infarto agudo do miocárdio ou necessidade de nova revascularização do vaso-alvo) em 1 ano em pacientes do "mundo real". MÉTODOS: O registro EINSTEIN é um estudo observacional prospectivo, unicêntrico, que incluiu consecutivamente 103 pacientes (152 lesões) tratados com o stent BiomatrixTM, eluidor de biolimus A9 e polímero biodegradável. RESULTADOS: A média das idades foi de 65,0±12,4 anos; o gênero masculino representou 83,5% dos pacientes; e 37,9% deles eram diabéticos. Em 1 ano, eventos adversos cardíacos maiores ocorreram em 11,7% dos pacientes, incluindo 2,9% de morte cardíaca, 4,9% de infarto agudo do miocárdio sem supradesnivelamento do segmento ST e 3,9% de revascularização do vaso-alvo. Trombose de stent esteve presente em apenas 1% (1 paciente) após o seguimento clínico de 1 ano. CONCLUSÃO: O presente registro sugere que os novos stents farmacológicos eluidores de biolimus A9 com polímero biodegradável são seguros e eficazes em pacientes da prática clínica diária, com baixas taxas de eventos adversos cardíacos maiores no longo prazo.

OBJECTIVE: To evaluate the incidence of major adverse cardiac events (cardiac death, or acute myocardial infarct, or target vessel revascularization) at one year in "real world" patients. METHODS: The EINSTEIN registry is an observational, prospective, single center study that consecutively included 103 patients (152 lesions) treated with the BiomatrixTM stent, a biolimus A9-eluting stent with biodegradable polymer. RESULTS: The mean age was 65.0±12.4 years; male gender represented 83.5% of the patients; and 37.9% of them were diabetic. At one-year, major adverse cardiac events occurred in 11.7% of the patients, including 2.9% of cardiac death, 4.9% of with non ST- segment elevation acute myocardial infarction, and 3.9% of target vessel revascularization. Stent thrombosis occurred in only 1% (1 patient) at one-yearfollow-up. CONCLUSION: The present Registry suggests that new generation biolimus A9 drug-eluting stents are safe and effective in a "real world", all-comers patients, showing low rates of major cardiac adverse events on long-term follow-up.

Estudo da ação da saliva nas propriedades mecânicas de protetores bucais para esporte / Study on the effect of saliva on the mechanical properties of mouth protectors for sports

Introdução - A eficiência e a durabilidade de protetores bucais para esporte dependem diretamente da forma com que são usados, pois sempre se apresentam em condições básicas de presença ou ausência de saliva. Para observar se essa condição de uso interfere em suas propriedades mecânicas este trabalho observa através de modelo experimental de arcos dentais obtidos em epóxi, acoplados a uma máquina universal de ensaios Kratos programada para movimento de compressão, o comportamento mecânico de protetores bucais para esporte, confeccionados -m copolímero de etileno e acetato de vinila ? EVA, posicionados no arco superior. Material e Métodos - Foram formados dois grupos de estudo: protetores bucais secos e protetores bucais saturados em saliva artificial, sendo estes últimos obtidos através de análise de saturação com o auxilio de balança analítica para observação de ganho de massa. As propriedades mecânicas observadasforam força máxima e energia absorvida. Resultados - Os resultados foram submetidos a analise estatística t-student (p < 0,05). Observou-se que no grupo dos protetores bucais saturados com saliva houve redução da força máxima (p = 0,00) devido a plastificação do material, responsável pela redução das forças intermoleculares ocasionando maior deformabilidade do protetor atestado pelo aumento da energia absorvida (p = 0,05) quando comparado ao grupo dos protetores secos. Conclusão - Conclui-se que a presença da saliva altera o comportamento mecânico do protetor bucal confeccionado em EVA tornando-o mais dúctil, portanto diminuindo a probabilidadede fraturas dentais e/ou lesões em tecidos circunvizinhos.

Introduction - The efficiency and durability of mouth protectors for sports depend directly on the way they are used, mainly because of their frequent exposure to saliva. To analise if this condition of use affects their mechanical properties, this paper observes, through the use of an experimental model made of epoxy, connected to an universal testing machine Kratos programmed to compress, the mechanical behaviour of mouth protectors for sports, made of ethylene and vinyl acetate copolymer - EVA, positioned on the superior arch. Two groups of study were created: dry mouth protectors and artificial saliva saturated mouth protectors, the second of which was analised with the use of an analitical balance to measure the level of saturation through the gain of mass.The mechanical properties observed were maximal strength and absorbed energy. The results were submitted to t-student statistical analisis method (p < 0,05). It was observed that, in the saturated mouth protectors group, the maximal strength diminished (p = 0,00) due to the material plastification, that caused a reduction in the intermolecular force and consequently a bigger deformation of the protector, confirmed by the increase in the absorbed energy (p = 0,05) when compared to the dry protectors group. It was concluded that the presence of saliva changes the mechanical behaviour of the mouth protector made of EVA, making it more flexible and reducing the probability of dental fractures and/or injuries on adjacent tissues.

Theophylline loaded gastroretentive floating tablets based on hydrophilic polymers: preparation and in vitro evaluation

This investigation describes the preparation and in vitro evaluation of gastroretentive floating tablet of theophylline. Two hydrophilic cellulose derivatives, Methocel K100M and Methocel K15MCR were evaluated for their gel forming and release controlling properties. Sodium bicarbonate and citric acid were incorporated as gas generating agents. The effects of soluble components [sodium bicarbonate and citric acid], gel forming agents and amount variation of theophylline on drug release profile and floating properties were investigated. Tablets were prepared by direct compression technique. Formulations were evaluated for in vitro buoyancy and drug release study was evaluated for eight hours using USP XXII paddle-type dissolution apparatus using 0.1N HCl as dissolution medium. The release mechanisms were explored and explained with zero order, first order, Higuchi and Korsmeyer equations. The release rate, extent and mechanisms were found to be governed by polymer and floating agent content. The content of active ingredient was also a vital factor in controlling drug release pattern. It was found that polymer content and amount of floating agent significantly affected the mean dissolution time, percentage drug release after 8 hours, release rate constant and diffusion exponent

Enhanced transdermal delivery of ketoprofen from bioadhesive gels

The aim of this study was to evaluate and compare the in vitro and in vivo transdermal potential of bioadhesive gels of ketoprofen by using gelling polymers like sodium carboxymethylcellulose, xanthan gum, poloxamer 407 and carbopol 934P as bioadhesive polymer with and without penetration enhancer [oleic acid]. The effect of oleic acid as a penetration enhancer was examined when it was added to the bioadhesive formulations. Gels were evaluated for bioadhesive force and viscosity. To study the in vitro potential of these formulations, permeation studies were performed with Franz diffusion cell using excised rat abdominal skin. Carrageenan induced rat paw edema model was used to investigate their in vivo performance. The commercial formulation of ketoprofen was used as a reference formulation. The in vitro permeation studies indicate that ketoprofen bioadhesive gel of poloxamer 407 with penetration enhancer was superior to gels of sodium carboxymethylcellulose and xanthan gum with penetration enhancer [oleic acid]. The permeation rate of ketoprofen from poloxamer 407 based bioadhesive gel with 15% v/w penetration enhancer was higher [rat abdominal skin flux = 0.421b 0.032 mg/cm2/h] than the permeation rate of sodium carboxymethylcellulose and xanthan gum based bioadhesive gel with 15% v/w penetration enhancer. In the paw edema test poloxamer 407 based bioadhesive gel with 15% v/w penetration enhancer showed the best permeation and effectiveness. The in vitro and in vivo studies showed that bioadhesive gels of ketoprofen could be used for effective therapy

Synthesis, characterization and electrical properties of novel conducting copolymer-nanocomposites via minimemulsion polymerization technique

A novel conducting copolymer nanocomnosites based on styrene [St]/maleic acid [MA] in presence of different carbon black [CB] percent ratios [1%, 3% and 5%] have been successfully synthesized via miniemulsion polymerization technique. A new method for the preparation of stable copolymer nanoemulsion composites of St/MA/CB via miniemulsion polymerization using high energy emulsitication technique by an equipment such as homogenizer. poly vinyl alcohol [PV A]/Sodium dodecyl benzene sulphonate [SDBS] as coemulsifiers and potassium persulphate [KPS] as an initiator. The polymerization reactions were done through 4 hr at 70°C. The indium and indium tin complexes of St/MA/CB copolymer nanot:mulsion composites were also prepared. As a result, the pure II1dium oxide and indium/tin oxide nano-particles are finely dispersed through the polymeric matrix to have an intimate interactions with the -COOH functional groups present in the copolymer nanocomposite. The obtained copolymer nanocomposites and their complexes were subjected to characterization via spectrophotometric measurements such as FT-IR, TEM and XRD analysis. The dc-electrical conductivity and Ac- electrical conductivity for the prepared copolymer nanocomposites and their complexes were investigated and gave promising results. The indiumcopolymer nano composite [In-St/MA/CB] gave us excellent results compared to those of traditional conducting polyanilines and showed higher electrical conductivity than those of St/MA/CB copolymer nanocomposites

Estudo comparativo do titânio versus polímero vegetal para a fixação interna rígida de fraturas orbitárias de coelhos / Comparative study of titanium versus polymer plant for the rigid internal fixation of fractures of orbital rabbits

Nas últimas décadas, os materiais utilizados para reparações ósseas de estruturas faciais tiveram um aprimoramento que muito facilitou a fixação interna rígida. Entretanto, este campo permanece aberto para as pesquisas até os dias atuais, uma vez que não se tem ainda o material ideal para este fim. Objetivo: avaliar a reparação de fraturas da parede orbitária usando a fixação interna rígida com miniplacas de titânio e de polímero vegetal comparando-as. Material e método: foi realizado um estudo experimental, prospectivo, na Faculdade de Medicina de Botucatu, no qual foram utilizados 45 coelhos albinos, submetidos a fratura do assoalho da órbita e divididos em três grupos esperimentais: G1, composto por animais que foram submetidos à fratura da órbita sem nenhum tipo de fixação ou redução da fratuta (grupo controle); G2 animais submetidos à fratura da órbita e fixação por miniplacas de titânio e G3, animais com fratura da órbita e fixação por miniplacas de polímero vegetal. Os animais foram radiografados logo após as fraturas realizadas e no momento do sacrifício, que ocorreu em 15, 30 e 60 dias após a cirurgia. Após o sacrifício, o material orbitário foi removido e preparado para exame histológico, realizado sob microscopia de luz. Resultados: Fraturas orbitárias conforme as induzidas no presente experimento possuem melhor resolução quando estabilizadas por miniplacas e parafusos, havendo semelhanças na consolidação óssea entre animais de G2 e G3, demonstrada pelo exame radiológico e histológico. A reação inflamatória foi mais acentuada nos animais do G3 quando a avaliação foi feita 15 dias após a cirurgia, decaindo com o decorrer do experimento. Conclusões: A miniplaca de polímero vegetal pode ser uma alternativa adequada para a reconstrução de fraturas orbitárias, dada a pequena reação inflamatória, capacidade de indução de crescimento ósseo e integração no local da fratura

Avaliação do grau de polimerização de duas resinas compostas utilizando luz halógena e dois diferentes tipos de LEDs / Evaluation of the polymerization degree of two resins composite using halogen light and two different types of LEDs

O objetivo deste estudo foi avaliar o grau de polimerização, por meio da microdureza Vickers, de duas resinas na cor A2 (Filtek Z250 e Solitaire 2). Para isso, foram utilizadas três diferentes fontes fotopolimerizadoras: XL 2500 (3M - fonte halógena), Ultrablue I (DMC - LED 1) e Ultrablue IS (DMC - LED 2). Foram confeccionados 30 moldes cilíndricos de policetal contendo uma cavidade de 3 x 2 mm de altura, que foram restaurados com as resinas em incrementos únicos e polimerizados por 20 s para todas as fontes. Foram realizadas 10 medidas de microdureza em cada corpo-de-prova (5 no topo e 5 no verso). Em seguida, foram feitas as médias dos valores da microdureza obtidas em cada face do corpo-de-prova, em que foi calculada a razão entre os valores obtidos a 2 mm de profundidade divididos pelos obtidos na superfície, obtendo-se assim os valores do grau de polimerização para cada grupo que foram submetidos à análise estatística. A análise de variância mostrou haver diferença estatisticamente significante (no nível de 5%) entre as fontes, entre as resinas e na interação fonte versus resinas. Para comparação entre as médias, foram calculados os valores de Tukey correspondentes que mostraram não haver diferenças significantes no grau de polimerização da resina Filtek Z250 entre a luz halógenae o LED 1, no entanto, houve diferença entre o LED 1 e o LED 2. Para a resina Solitaire 2, não houve diferença estatisticamente significante no grau de polimerização entre a fonte halógena e o LED 2, mas houve entre o LED 1 e o LED 2 e também entre a luz halógena e o LED 2. Porém, as únicas fontes de luz que obtiveram grau de polimerização satisfatório (no mínimo 80% do grau de polimerização) foi a fonte halógena e o LED 2 quando polimerizaram a resina Filtek Z250. Pode-se concluir que o LED 1 não polimerizou adequadamente nenhuma das resinas estudadas e o LED 2 teve comportamento semelhante à fonte halógena para as duas resinas.

Uso do polímero de mamona (impermaster) na impermeabilização de lesões podais de bovinos / The efficiency of poliuretan polimer (impermaster) in readering foot lesions impermeable

Este trabalho foi realizado com o objetivo de relatar o uso do polímero poliuretano de mamona (Impermaster®) na impermeabilização de lesões podais de doze bovinos. Foram tratadas duas vacas da raça Holandesa Preto e Branco com necrobacilose plantar; três vacas Jérsey com úlceras de sola profundas; uma fêmea Jérsey com necrobacilose associada a perda de 60% da falange distal; e seis touros (três da raça Simental, dois da Charolesa, um da Holandesa Preto e Branco) com feridas extensas na região da muralha em um Simental, quatro em sola e um em pinça, sendo quatro casos no membro pélvico e dois nos membros torácicos. O tratamento constituiu-se da lavagem e debridamento da ferida com posterior aplicação de uma pasta composta por óxido de zinco, sulfato de cobre, sulfametazina, nitrofurazona e dimetil sulfóxido. Em seguida, as feridas foram protegidas e impermeabilizadas com alcatrão vegetal e mantidas nessa condição durante 20 dias, quando foram reavaliadas, limpas e impermeabilizadas com polímero poliuretano de mamona preparado com duas partes de Impermasterpol para uma parte de Impermaster-pré. Após o preparado ter adquirido consistência de goma, foi aplicado e moldado na lesão com auxílio de uma espátula, mantendo-se o membro do animal suspenso durante 30 minutos, para endurecimento do polímero. Os animais forma mantidos em observação durante 60 dias antes de serem submetidos a nova avaliação, limpeza e impermeabilização das feridas com o mesmo produto. Aos 120 dias, os animais foram liberados para as respectivas propriedades sem nenhum tipo de afecção podal.

Synthesis and characterization of poly(p-phenylene vinylene)

Poly (p-phenylene vinylene) (PPV) was synthesized from p-xylylene bis(tetrahydrothiophenium chloride) using the Wessling route and characterized by Fourier Transform Infra-Red (FTIR) and UV-visible (UV-VIS) spectroscopic techniques. The significance of thermal treatment along with evolution of precursor polymer to polymer PPV was also studied through these spectroscopic techniques. Thermally Stimulated Current (TSC) measurements indicated the presence of crystallization, sulphonium group which occurred through the evolution from precursor polymer to polymer PPV during thermal treatment.

Synthesis, characterization and electrial properties of poly N-Phenyl 2-Naphthyl amine and poly N-Ethyl aniline

Poly n-phenyl-2-naphthyl amine [PNPNA] and poly N-ethyl aniline [PNEA] have been prepared using potassium persulphate as an oxidizing agent. The polymers were characterized by various methods using spectrophotometric measurements, e.g., I.R. and UV-visible. Thermal gravimetric analysis [TGA] for PNEA indicated its great thermal stability up to 430 degree. A.C. resistivity and capacitance measurements have been used to characterize the electrical properties of the prepared polymers in the temperature ranges from 25 degree to 160 degree for and from 25 degree to 240 degree for PNEA. Log p, capacitance, Ea and dielectric constant values were obtained at different frequency ranges from 5OHz up to 100 kHz. The results suggest hopping conduction mechanism for the PNPNA pellets, the increase in conductivity being governed by the interchain hopping of polarons acting as charge carriers. The PNEA pellets, on the other hand, showed higher resistivity values at all frequency ranges than those of PNPNA. Also the A.C. resistivity tends to become temperature independent. Accordingly, the conductivity increased with increasing frequency. This behaviour is attributed to the presence of ethyl groups in the polymer chain that introduce new trap levels within the localized states

Recent advances in pharmaceutical applications of solid phase synthesis

Merrifield in 1963 introduced his solid phase technique for synthesis of peptides. The advantage of this approach is that the growing peptide chain is firmly attached to a completely insoluble solid particle and can be washed free of reagents and by-products. It was for reason that the term solid phase peptide synthesis was introduced to describe the new method. This method lends itself to automation and provides a route to the synthesis of many of the higher molecular weight polypeptides and oligonucleotides which have not been accessible by conventional procedures

Selective cleavage of N-terminal amino acid in a peptide by polymeric cobalt (III) triene complex.

Cellulose was functionalized to incorporate triethylenetetramine group. This was in turn converted into the polymeric analogue of cobalt(III)triene complex. The polymeric complex reacts with peptides resulting in the cleavage of amino end amino acid, thus suggesting the applicability of the polymeric reagent as a solid phase reagent for N-terminal determination.

Biologically active polymer supports based on cellulosic derivatives: synthesis and kinetic study.

Bioactive cellulose derivatives have been synthesised by coupling enzymes/antibiotics on carboxymethyl cellulose acid chloride and cellulose carbonate. The effect of pH and temperature on the enzymatic activity of amyloglucosidase immobilised on cellulose carbonate was studied. Michaelis-Menten kinetics have been obeyed to the first degree of approximation despite the restricted mobility of the attached enzyme on the polymer support. Lineweaver-Burk plots for the amyloglucosidase immobilized on carboxymethyl cellulose acid chloride at ambient pH with cellulose carbonate at pH 8 have also been plotted. The Michaelis-Menten constant for the immobilized amyloglucosidase on cellulose carbonate at pH 8 was 9.1 mM, and the activation energy for starch hydrolysis was 21.8 kcals/mole.