Academic literature on the topic 'Guar gum films'

Fourier Transformed Infrared Spectroscopy (FTIR) was used to study the effect of water immersion of guar gum, gelatin and pektin films. Animal-derived gelatin, citrus-derived pektin and natural guar gum made from guar seeds was used to manufacture thin films (using a 2% concentration starting solution) by casting. The biodegradable polymer films were immersed in distilled water before FTIR analysis to absorb water. The immersion time varied between 1 to 15 sec for not to make hydrocolloids, only observe swelling. After 20 sec the biofilms effectively dissolved in the distilled water.

AbstractThis study investigated the effect of the guar gum content on the degradation behavior of the polyester and polyether polyurethane acrylate composites under outdoor soil-burial exposure. Polyurethane acrylates-guar gum composites were characterized before and after soil degradation by Fourier transform infrared spectroscopy (FTIR), mechanical measurements and scanning electron microscopy (SEM). The results showed that the addition of guar gum produces significant improvement in the degradation rate of these composites. The guar gum filler’s susceptibility to humidity and to soil microorganisms resulted in significant chemical and morphological changes in the entire structure of the composite. Guar gum incorporation into the matrix of the crosslinked polyurethane acrylates leads to a significant decrease in the mechanical properties of the composite films after soil burial exposure.

Guar gum hydrogels may be dried to form polymer films which have the potential for use as biodegradable alternatives to polymers such as low-density polyethylene. In this study, the tensile strength and tensile modulus of guar gel films having moisture contents ranging between 15% and 18% (wet basis) were measured at a strain rate of 1 mm min−1. Mean tensile strengths of the films ranged between 25 MPa and 40 MPa (dependent on composition) which is of similar magnitude to the tensile strength data for polyethylene and cellophane that are reported in the literature. The mean tensile modulus of the films (1.5–2.5 GPa) was higher than the tensile modulus values reported for low-density polyethylene but comparable to those for cellophane (3 GPa).

The objective of this research was to investigate the effect of pH(7.0, 8.0, 9.0, 10.0) on the properties of soy protein isolate (SPI)/guar gum (GG)composite films casted with 0.2 %(w/v)guar gum polysaccharide, 5.0 %(w/v)SPI, 1.5 %(w/v)glycerol plasticizer, and 4:1(v/v) mixture of distilled water and anhydrous alcohol. Composite membranes from different pH conditions were evaluated from following aspects: tensile strength (TS), elongation at break (EB), water vapor permeability (WVP), water solubility (WS) and surface hydrophobicity(SH)

By mixing a guar gum (GG) solution with a nanocrystalline cellulose (NCC) dispersion using a novel circular casting technology, we manufactured biodegradable films as packaging materials with improved optical and mechanical properties.

This research work was aimed to develop the telmisartan fast dissolving films. Fast dissolving films allow rapid drug dissolution in the oral cavity and thereby bypass the first pass metabolism. Solid dispersions of telmisartan using natural polymers such as hupu gum (HG), guar gum (GG) and xanthan gum (XG) were prepared by kneading technique and the optimized solid dispersion was exploited in the development of rapidly dissolving film. Telmisartan films were prepared by solvent casting method using different grades of HPMC (E5, 50 cps and K4M). Six formulations (FT1-FT6) of telmisartan films were prepared and evaluated for their physical characteristics such as thickness, tensile strength, percentage elongation, weight variation, folding endurance, drug content uniformity and surface pH and gave satisfactory results. The compatibility of the drug in the formulation was confirmed by FTIR and DSC studies. The formulations were subjected to disintegration, in vitro drug release and pharmacodynamic studies on spontaneous hypertensive rats (SHR). Amongst the formulations of FT1-FT6, FT6 was found as best formulation which contains HPMC E5 and telmisartan solid dispersion with guar gum at weight ratio of 1:2 and showed excellent film forming characteristics such as disintegration time at 42 sec and percentage drug release 97.98% within 10 minutes. The optimized film formulation (FT6) showed excellent stability over 45 days when stored at 40°C/60% RH. The pharmacodynamic study in SHR proved that fast dissolving films of telmisartan produced a faster onset of action.

The brown planthopper (BPH), Nilaparvata lugens (Stål), is the most notorious rice insect pest. In order to repel BPH effectively while being environmentally friendly, a new film based on guar gum incorporated with citral (GC film) was formulated. A toxicity bioassay of citral and guar gum at different proportions (ratios of 3:1, 2:1, 1:1, 1:2, and 1:3 in w/w) of GC film-forming emulsion to BPH was performed with the rice stem dipping method. Results showed that the most effective ratio of citral to guar gum was 1:1 with the median lethal concentration (LC50) of 4.30 mg/mL, far below the LC50 of guar gum (GG)/citral individual (141.51 and 44.38 mg/mL, respectively). The mortality of BPH adults and nymphs in the third instar treated with different dilution multiples of GC film-forming emulsion ranged from 46.67% to 82.22% and from 37.78% to 71.11%, respectively. These indicated that GC film-forming emulsion had a direct toxicity on BPH, and the mixture of citral and GG had synergistic interactions. Subsequently, Fourier-transform infrared spectroscopy showed that the incorporation of guar gum with citral was successful and did not result in the formation of new chemical bonds. The GC film exhibited a darker color and rougher surface topography with larger apertures and deeper gullies (Ra = 1.42 nm, Rq = 2.05 nm, and Rmax = 25.40 nm) compared to the guar gum film (GG film) (Ra = 1.00 nm, Rq = 1.33 nm, and Rmax = 16.40 nm), as determined by transmission electron microscopy and atomic force microscopy. The GC film exhibited a 50.4% lower solubility in water (30.30% vs. 15.00%) and 71.3% oxygen permeability (8.26 × 10−9 vs. 2.37 × 10−9 cm3/m2·d·Pa) (p < 0.05) but did not demonstrate any significant difference in mechanical properties, such as thickness (39.10 vs. 41.70 mm), tensile strength (41.89 vs. 38.30 N/mm2), and elongation at break (1.82% vs. 2.03%) (p < 0.05) compared to the GG film. Our findings established a link between physicochemical properties and bioactivity, which can provide useful information on developing and improving GC films and may offer an alternative approach for the control of BPH in the near future.

Visando o aumento da biodisponibilidade dos compostos bioactivos administrados por via oral (com especial ênfase para a absorção bucal), o plano de trabalhos deste programa doutoral visou a optimização de formulações de filmes orais e de micro- e nanopartículas que, conjugados constituam sistemas inovadores com atividade sinérgica. As moléculas bioactivas seleccionadas para estudar o comportamento e eficácia das formulações optimizadas foram a cafeína e dois péptidos presentes na proteína do soro do leite com actividades antihipertensora (sequência: KGYGGVSLPEW) e relaxante (sequência: YLGYLEQLLR). O processo de optimização das formulações foi iniciado pela seriação e comparação preliminar dos excipientes para a produção de filmes e micro/nanopartículas. No primeiro estudo realizado, foram optimizadas e comparadas duas formulações de filmes (usando-se os polímeros carboximetilcelulose sódica e gelatina tipo A) como veículos para libertação oral de cafeína. Verificou-se, através da análise por espectroscopia no infravermelho por transformada de Fourier com reflectância total atenuada (FTIR-ATR), que a estrutura química da cafeína não fora alterada durante o processo de produção dos filmes. Concluiu-se também, através do ensaio de dissolução estabelecido pela Farmacopeia Americana (USP), que os filmes produzidos com gelatina tipo A permitiram uma libertação mais lenta da cafeína ao passo que os filmes de carboximetilcelulose apresentaram um perfil de libertação imediata. Em concordância, o valor de permeabilidade aparente da cafeína, determinada através do ensaio de permeabilidade ex vivo, através de excisões de intestino delgado de origem porcina, verificou-se superior quando esta foi veiculada pelos filmes de carboximetilcelulose, comparativamente com os filmes de gelatina tipo A. O tempo de desintegração de ambas as formulações mostrou-se, contudo, demasiado alto para formulações orodispersíveis, não ocorrendo desintegração completa após 30 segundos. Ainda na sequência da escolha do polímero com melhores características para integrar a composição de filmes orais, uma nova formulação contendo goma-guar foi optimizada por desenho factorial. Os filmes de goma-guar apresentaram características mecânicas e físico-químicas superiores às verificadas para os filmes de carboximetilcelulose e gelatina, tomando-se como factores de decisão a capacidade de absorção de água, a erosão em saliva artificial e o tempo de desintegração apresentados pelos filmes de goma-guar. Procedeu-se também à optimização (por desenho fatorial) de uma formulação de micropartículas de alginato que garantissem, em conjunto com os filmes de goma-guar, uma libertação controlada de cafeína, assim como uma maior biodisponibilidade da mesma. A associação de micropartículas de alginato aos filmes de gomaguar – GfB - não induziu alterações das características químicas da cafeína, de acordo com o verificado por FTIR-ATR, nem toxicidade para as linhas celulares usadas para mimetizar as mucosas bucal (TR146) e intestinal (Caco-2/HT29-MTX), de acordo com os resultados obtidos pelo ensaio de viabilidade celular MTT (Brometo de 3-(4,5-Dimethylthiazol-2-yl)-2,5- Diphenyltetrazólio). Adicionalmente, os perfis de libertação e permeabilidade in vitro (através das linhas celulares TR146 e Caco-2/HT29-MTX cultivadas em camada) e ex vivo (através de epitélio intestinal de origem porcina) mostraram-se mais lentos que os observados para as micropartículas de alginato, filmes de goma-guar ou com a solução controlo de cafeína. A formulação GfB promoveu o aumento do contacto efectivo entre a cafeína e o epitélio bucal, oferecendo uma permeação mais completa ao longo do tempo. De forma a incrementar também a biodisponibilidade do péptido KGYGGVSLPEW com actividade anti-hipertensora, as micropartículas de alginato foram substituídas por nanopartículas de ácido poli(láctico-co-glicólico) – PLGA - por estas oferecerem uma eficácia de associação superior, assim como um maior potencial de permeação das membranas biológicas, dado o tamanho de partícula ser significativamente inferior. A formulação de nanopartículas de PLGA foi optimizada por desenho factorial. O sistema compreendido pelas nanopartículas de PLGA associadas aos filmes de goma-guar (GfNp) não comprometeu a viabilidade das linhas celulares TR146 e Caco-2/HT29-MTX às concentrações testadas. O sistema desenvolvido promoveu a libertação e permeabilidade controladas do péptido, através das células TR146 e Caco-2/HT29- MTX cultivadas em camada, comparativamente com os filmes e nanopartículas isoladamente, assim como com a solução de péptido livre (controlo). Contudo, a permeabilidade aparente verificou-se superior para a formulação GfNp, comparativamente com as restantes formulações. Estes resultados deveram-se ao contacto íntimo entre o péptido e o epitélio absorptivo, promovido pela formulação GfNp. Verificou-se ainda, através da realização do ensaio in vitro da capacidade de inibição da enzima conversora da angiotensina I, que o péptido transportado por GfNp apresentava a maior actividade anti-hipertensora após ser sujeito à simulação do tracto gastrointestinal, comparativamente com o péptido transportado pelas nanopartículas ou filme, isoladamente, ou com a solução de péptido livre. O sistema previamente optimizado para a libertação do péptido antihipertensor foi também usado de forma a incrementar a biodisponibilidade do péptido relaxante alfa-casozepina (sequência: YLGYLEQLLR). Através do ensaio MTT, foi possível concluir que nenhuma das formulações comprometeu a viabilidade da linha celular TR146 e da co-cultura Caco-2 /HT29- MTX. Por isso, a permeabilidade do péptido, sujeito às condições do tracto gastrointestinal simulado, através dos modelos in vitro bucal e intestinal foi estudada. Verificou-se que a associação de nanopartículas de PLGA com filmes de goma-guar promoveu um aumento da permeabilidade face às nanopartículas e filmes não conjugados, assim como com o péptido em solução (controlo). Estes resultados estão correlacionados com o incremento da mucoadesão conferida pela associação das nanopartículas de PLGA com os filmes de goma-guar, verificada através da análise da adesividade e trabalho de adesão à língua de vaca. Validada a efectividade das formulações para a libertação e permeabilidade de cafeína e péptidos bioactivos, foram realizados estudos preliminares de modo a verificar a estabilidade da formulação GfB e a compreender a opinião de potenciais futuros consumidores face aos produtos desenvolvidos. As formulações foram sujeitas a condições de degradação acelerada (i.e. 40 ºC e 75% de humidade relativa) de acordo com a International Conference of Harmonization (ICH), não se verificando alterações químicas da cafeína em nenhum dos tempos de amostragem (imediatamente após a preparação da formulação e após 3, 6 e 9 meses) através da análise do espectro obtido por ATR-FTIR, assim como dos tempos de retenção em HPLC-UV. Verificou-se ainda um aumento significativo do conteúdo em água de GfB ao longo dos tempos de amostragem. Por fim, um estudo por focus group e um estudo de análise sensorial com um painel naive permitiram compreender a adequabilidade dos sabores propostos, assim como a tolerância à acidez e amargor por parte do consumidor. Observou-se uma ligeira tendência para a aceitação do sabor a menta e alguma tolerância ao amargor e acidez quando a menta foi usada na formulação. Os sistemas para libertação oral de compostos bioactivos, desenvolvidos e optimizados no âmbito desta tese, induziram melhorias significativas no comportamento farmacocinético in vitro dos compostos veiculados. De facto, a associação de filmes orais com micro- ou nanopartículas pode representar um novo sistema de libertação que ofereça maior efectividade e adesão por parte do consumidor/utente.
Aiming for the protection and absorption enhancement of bioactive compounds administered by oral route (with special focus on buccal absorption), this thesis had as goals, the optimization of oral films and micro/nanoparticles which, through conjugation of both, worked as innovative oral delivery systems with synergic activity. The bioactive molecules selected to study the behaviour and efficacy of the optimized formulations were caffeine and two whey-derived peptides with antihypertensive and relaxing activities (sequences: KGYGGVSLPEW and YLGYLEQLLR, respectively). The optimization process began with the selection and preliminary comparison of the characteristics of the excipients to be used to prepare films. Indeed, the first study included the optimization and comparison of two film formulations as carriers for the oral release of caffeine, prepared using sodium carobymethylcellullose and type A gelatine as polymers. It was observed by the analysis of the spectra obtained by Fourier-transformed infrared spectroscopy with attenuated total reflectance (FTIR-ATR) that caffeine chemical structure was not altered during the film production process. It was also observed, through the dissolution assay established by the United States Pharmacopoeia (USP), that type A gelatine films offered a slow caffeine release, whereas caroboxymethylcellulose films offered a burst release profile. Accordingly, the apparent permeability of caffeine observed from the ex vivo permeability assay, across small intestine tissues from porcine origin, was higher for carboxymethylcellullose films than for type A gelatine films. Nonetheless, disintegration time of both formulations was too high to meet the criteria of orodispersible formulations, taking longer than 30 s to achieve total disintegration. Still in the process of choosing the best polymer to integrate the composition of oral films, a new formulation containing guar gum as polymer was optimized by factorial design. Guar gum films presented superior mechanical and physico-chemical characteristics than carobxymethylcellullose or type A gelatine films, mainly regarding water-uptake capacity, erosion in artificial saliva and disintegration time. Furthermore, a formulation of alginate microparticles was also optimized by factorial design to associate with guar gum films and guarantee the controlled release of caffeine, as well as an increased bioavailability. The association of alginate beads to guar gum films – GfB – did not induce alterations in the chemical characteristics of caffeine, as outlined in the data obtained by FTIR-ATR, nor cytotoxicity to the cell lines used to mimic the buccal (TR146) or intestinal (Caco-2/HT29-MTX) mucosa, as determined by MTT ((3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide). Additionally, the release and in vitro (through TR146 and Caco-2/HT29-MTX cell lines) and ex vivo (through porcine intestinal mucosa) permeability profiles of caffeine from GfB was slower when compared with alginate microparticles, guar gum films or caffeine control solution. GfB also increased the effective contact between caffeine and buccal epithelia, offering a more complete permeation along time. Further, aiming to increment the bioavailability of the peptide KGYGGVSLPEW with antihypertensive activity, alginate beads were replaced with poly(lactic-co-glycolic) acid (PLGA) nanoparticles, since the last offer a higher association efficiency and a higher permeability of biologic membranes, due to the significantly lower particle size. The formulation of PLGA nanoparticles was optimized by factorial design. The delivery system comprising PLGA nanoparticles into guar gum films (GfNp) did not compromise the viability of the cell lines TR146 and Caco-2/HT29-MTX at tested concentrations. Moreover, GfNp promoted a slower peptide release and in vitro permeability across TR146 and Caco-2/HT29-MTX cell layers when compared with the films and nanoparticles alone or with a free peptide solution (control). However, apparent permeability was higher for GfNp when compared with remaining formulations. Results may be due to the intimate contact between the peptide and the epithelia, promoted by GfNp. It was also possible to observe that the peptide carried by GfNp presented a higher in vitro capacity to inhibit the angiotensin-converting enzyme after being subjected to the simulation of gastrointestinal tract, therefore presenting higher antihypertensive potential, when compared with the peptide carried by the nanoparticles or films alone or with the control solution (free peptide). The previously optimized system as carrier and delivery system for the antihypertensive peptide was also used to enhance the bioavailability of the relaxing peptide alpha-casozepine (sequence: YLGYLEQLLR). It was possible to conclude, through MTT assay, that none of the formulations compromised cell viability of TR146 cell line or Caco-2/HT29-MTX co-culture. Moreover, peptide permeability across in vitro buccal and intestinal epithelial models, while being subjected to simulated gastrointestinal tract, was higher and faster (higher apparent permeability) for the association of guar gum films with PLGA nanoparticles, when compared with PLGA nanoparticles or guar gum films alone or with the free peptide solution (control). Obtained results are related with the increased mucoadhesion conferred by the association of PLGA nanoparticles with guar gum films, verified through the analysis of adhesivity and work of adhesion to cow tongue. After validation of the effectivity of the formulations regarding release and permeability of caffeine and bioactive peptides, preliminary studies were performed to understand the stability of GfB and the opinion of potential future consumers of the developed products. Formulations were subjected to accelerated degradation conditions according to the International Conference of Harmonization (ICH) and it was verified, through analysis of spectra (by FTIR-ATR spectroscopy) and retention times (by HPLC-UV), that no chemical alterations of caffeine molecule carried by GfB were observed in any of the set time points (i.e. immediately after preparation of GfB and 3, 6 and 9 months after preparation, under accelerated degradation conditions – 40 ºC and 75% of relative humidity). Moreover, an increased water content was observed along the three time points. Further, a focus group and a sensory analysis study with a naïve panel allowed to understand the suitability of the flavours but also the tolerability to acidity and bitterness by the consumer. A slight tendency to the acceptance of mint flavour and some tolerance to bitterness and acidity was verified when mint was used in the formulation. Developed and optimized oral delivery systems in the scope of the present thesis induced significant improvements on the in vitro pharmacokinetic behaviour of carried bioactive molecules. Indeed, the association of oral films with micro- and nanoparticles may represent conceptually new delivery systems that offer higher effectivity and consumer/patient compliance.

The impact that e-learning has had on the workplace over the last 20 years is paramount. From video-conferencing to desktop Webinars, business has included technology and distance learning solutions in its model of human resource development. However audio and video podcasting as mobile learning stands to provide a very different dimension of distance learning. Instead of being restrained and constrained to a desktop or conference room, professional learning truly can be “anytime, anywhere.” From the office, to the gym, the shopping mall, to the beach, veteran professionals and young adults alike are exploring how to use mobile technology to improve their personal and professional learning. This article provides a background on this wave of mobile learning, including how podcasting has arisen, lessons learned, and growing trends. In addition, it examines issues that face HRIS (human resources information system), e-HRM (electronic human resource management system), individuals and professionals within mobile learning. Podcasts are digital audio files, which are hosted on the Internet and published via a special scripting language. Podcasts are usually produced in a series, so that there are more than one episode and the scripting language, XML (extensible markup language) and RSS (really simple syndication), enables updates of the series to be sent to the listener’s computer or wireless device automatically (King & Gura, 2007). This article begins with an introduction to the topic of podcasting and podcasting as mobile learning. The background section provides a detailed definition of this emergent technology and usage, while later the discussion turns to the critical issue of copyright and podcasting. Considering the forms and possibilities for professional learning through this mobile technology is a vital component of this article before we turn to the lively topic of trends in new and social media, which includes podcasting. The conclusion of the article brings us full circle as we consider how this fits together for podcasting as mobile learning.