RESUMO
UV-induced peroxidation is a significant factor in skin damage. Some natural products have been utilized to protect the skin. However, most of them suffer from issues such as poor bioavailability. A promising strategy is to prepare them as safe and convenient gels. In this study, we constructed Silybin Nanocrystal Gel (SIL-NG). Tea saponin, a spatial stabilizer that we have previously reported, was used to prepare SIL-NS and subsequently combined with xanthan gum to prepare SIL-NG with an excellent safety profile. This nanogel with a natural stabilizer has a suitable ductility and shows a good safety profile in vitro and in vivo. In L929 cells, SIL-NG was able to reduce H2O2-induced ROS levels. In addition, SIL-NG exhibited better antioxidant activity compared to SIL-NS. SIL-NG was able to reduce UVB irradiation-induced oxidative damage in mice, significantly increase SOD activity, and reduce MDA levels. In conclusion, our work gives a new perspective on the treatment of UV skin damage using natural ingredients.
Assuntos
Peróxido de Hidrogênio , Nanopartículas , Animais , Camundongos , Silibina , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo , Antioxidantes/farmacologia , Pele/metabolismo , Géis/metabolismo , Chá/química , Raios UltravioletaRESUMO
A plain symbiotic almond yogurt-like product was formulated and developed using a plant-based starter YF-L02 (Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus supplemented with Lactobacillus acidophilus, Lactobacillus paracasei, and Bifidobacterium animalis) and inulin; 0.6% polymerized whey protein (PWP), 0.3% pectin, and 0.05% xanthan gum were optimized for the formula of the almond yogurt alternative. Two groups with/without calcium citrate and vitamin D2 were prepared and analyzed for chemical composition, changes in pH, viscosity, and probiotic survivability during storage at 4 °C for 10 weeks. The results showed that (1) over 10 weeks storage, the differences in the pH, viscosity, and probiotic survivability between the control and the fortified samples were not significant (P > 0.05); (2) the pH of both yogurt samples decreased 0.2 units while their viscosity slightly increased during storage; (3) the populations of L. paracasei and B. animalis remained above 106 cfu/g during the storage, whereas the population of L. acidophilus decreased dramatically during the first 4 weeks, especially the control group; (4) the microstructure was examined by scanning electron microscopy, revealing a compact and denser gel structure formed by 0.6% PWP with the presence of 0.3% pectin and 0.05% xanthan gum. In conclusion, PWP might be a proper gelation agent for the formulation of symbiotic almond yogurt alternative. PRACTICAL APPLICATION: In this study, polymerized whey protein was used as a gelation agent to formulate symbiotic almond yogurt alternatives with comparable physical texture and probiotic survivability to dairy yogurt during storage. This technology may be used for the development of plant-based fermented foods.
Assuntos
Lactobacillus acidophilus/crescimento & desenvolvimento , Lactobacillus delbrueckii/crescimento & desenvolvimento , Probióticos/química , Prunus dulcis/química , Streptococcus thermophilus/crescimento & desenvolvimento , Proteínas do Soro do Leite/química , Iogurte/análise , Fermentação , Géis/química , Géis/metabolismo , Inulina/química , Inulina/metabolismo , Lactobacillus acidophilus/metabolismo , Lactobacillus delbrueckii/metabolismo , Viabilidade Microbiana , Pectinas/química , Pectinas/metabolismo , Polimerização , Prunus dulcis/metabolismo , Prunus dulcis/microbiologia , Streptococcus thermophilus/metabolismo , Viscosidade , Proteínas do Soro do Leite/metabolismo , Iogurte/microbiologiaRESUMO
This study aims to develop in situ microemulsion-gel (ME-Gel) obtained from hydroxypropyl methylcellulose (HPMC) films for transdermal administration of Zidovudine (AZT). Firstly, HPMC films containing propylene glycol (PG) and eucalyptus oil (EO) were obtained and characterized. Later, a pseudo-ternary phase diagram composed of water, EO, tween 80 and PG was obtained and one microemulsion (ME) with a similar proportion of the film components was obtained. ME was transformed in ME-Gel by the incorporation of HPMC. Finally, HPMC films were hydrated with Tween 80 solution to yield in situ ME-Gel and its effect on AZT skin permeation was compared with HPMC film hydrated with water (F5hyd). The results showed that the ME and ME-Gel presented a droplet size of 16.79 and 122.13⯵m, respectively, polydispersity index (PDI) < 0.39 and pH between 5.10 and 5.40. The incorporation of HPMC resulted in viscosity about 2 times higher than the use of ME. The presence of AZT did not alter the formulation properties. The in situ ME-Gel promoted a two-fold increase in the permeated amount of AZT compared to F5hyd. The results suggest that it was possible to obtain an ME-Gel in situ from HPMC films and that its effect on transdermal permeation of AZT was significant.
Assuntos
Metilcelulose/química , Pró-Fármacos/química , Zidovudina/química , Administração Cutânea , Animais , Emulsões/administração & dosagem , Emulsões/química , Emulsões/metabolismo , Óleo de Eucalipto/administração & dosagem , Óleo de Eucalipto/química , Óleo de Eucalipto/metabolismo , Géis/administração & dosagem , Géis/química , Géis/metabolismo , Masculino , Metilcelulose/administração & dosagem , Metilcelulose/metabolismo , Tamanho da Partícula , Pró-Fármacos/administração & dosagem , Pró-Fármacos/metabolismo , Propilenoglicol/administração & dosagem , Propilenoglicol/química , Propilenoglicol/metabolismo , Ratos , Ratos Wistar , Pele/química , Pele/metabolismo , Absorção Cutânea , Propriedades de Superfície , Zidovudina/administração & dosagem , Zidovudina/metabolismoRESUMO
This study investigated effects of fermentation on compositions, color, and functional properties of gelatinized potato flours from Atlantic and Kexin No.1 cultivars. Atlantic flour (AF) and Kexin No.1 flour (KF) were fermented using 1% yeast concentration, respectively. Fermentation further improved the nutritional and physicochemical features of gelatinized potato flours by means of increased protein and ash contents, and decreased the levels of moisture, lipid, soluble amylose, amylopectin, and total starch. The lightness and whiteness of potato flours were enhanced with the increase in fermentation time. There are gradual increases in water absorption index, emulsifying capacity and emulsifying stability of potato flours during fermentation. However, bulk density of them slightly reduced with the increase in fermentation time. In addition, fermentation has no significant effect on freeze-thaw stability of gelatinized potato flours. These results indicate that yeast fermentation could enhance certain processing characteristics of potato flours and improve the applicability of them in food formulations. PRACTICAL APPLICATION: Lately, China has started national project regarding the use of potato flour in foods. However, due to dark color and low protein content of potato flours, their application in food formulations was limited. This study analyzed the possible mechanisms by which yeast fermentation improved the nutritional and functional characteristics of Atlantic flour (AF) and Kexin No. 1 flour (KF). From applications standpoint, findings of this study could provide knowledge on the selection of potato flours for various food formulations.
Assuntos
Farinha/análise , Solanum tuberosum/química , Leveduras/metabolismo , Amilose/química , Amilose/metabolismo , China , Cor , Fermentação , Farinha/microbiologia , Géis/química , Géis/metabolismo , Solanum tuberosum/metabolismo , Solanum tuberosum/microbiologia , Amido/química , Amido/metabolismoRESUMO
The addition of gelling polysaccharides to sport-drinks may provide improved tolerability of drinks with high concentration of digestible carbohydrates (CHO), otherwise known to increase the risk of gastro-intestinal complaints among athletes under prolonged exercise. The physico-chemical properties of a drink containing 14 wt% of digestible CHO (0.7 : 1 fructose and maltodextrin-ratio), 0.2 wt% of HM-pectin/alginate and 0.06 wt%. sodium chloride were examined under in vitro gastric conditions using rheology and large deformation testing. The in vivo gelling behaviour of the drink was studied using magnetic resonance imaging of subjects at rest together with blood glucose measurements. The in vivo results confirm gelation of the test drink, with no gel remaining in the stomach at 60 min and blood glucose values were similar to control. The physico-chemical characterisation of the acidified test drink confirms the formation of a weak gel through which low Mw CHO can diffuse.
Assuntos
Alginatos/química , Alginatos/metabolismo , Bebidas/análise , Mucosa Gástrica/metabolismo , Pectinas/química , Pectinas/metabolismo , Adulto , Atletas , Glicemia/metabolismo , Carboidratos da Dieta/metabolismo , Feminino , Géis/química , Géis/metabolismo , Humanos , Imageamento por Ressonância Magnética , Masculino , Reologia , Estômago/diagnóstico por imagem , Adulto JovemRESUMO
Jabuticaba is a native Brazilian fruit rich in phenolic compounds as anthocyanins, showing several benefits for human health but a high sensibility to physicochemical digestion conditions. Gellan is a biopolymer that could be used as a material to protect and carry bioactive compounds, since this polysaccharide is resistant to gastric pH conditions. In this context, gellan gels containing jabuticaba extract were produced using two different ionic strength values (adding calcium ions), which resulted in varied structures. These gels were subjected to two different in vitro digestion processes, modifying the type of mechanical forces applied to simulate stomach and intestine movement conditions. Anthocyanins release (by pH differential method), mechanical properties, confocal and light microscopy of gels were evaluated during in vitro digestibility. Results showed that jabuticaba extract exerted effect on gels mechanical-structural properties, since an increase of stress at rupture (hardness) and a decrease of strain at rupture (deformability) were observed only in gels without calcium addition. Although all gellan gels have improved anthocyanins retention during simulated gastrointestinal digestion process, gels without calcium were more efficient. Our results demonstrated that gellan gels could act as good carriers for anthocyanins, but their efficiency is dependent on the matrix composition, demonstrating that specific studies should be accomplished to determine which changes may occur in the matrix after bioactive addition. Furthermore, our results showed that the type of mechanical forces applied during in vitro digestion is an important variable, since the use of compression (a more similar-to-in vivo system) rather than shear forces increased the release of anthocyanins.
Assuntos
Frutas/química , Géis/metabolismo , Myrtaceae/química , Extratos Vegetais/metabolismo , Polissacarídeos Bacterianos/metabolismo , Antocianinas/metabolismo , Brasil , Digestão , Géis/química , Fenômenos Mecânicos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacocinética , Polissacarídeos Bacterianos/químicaRESUMO
Background and objectives: Arabinoxylans (AX) can gel and exhibit antioxidant capacity. Previous studies have demonstrated the potential application of AX microspheres as colon-targeted drug carriers. However, the cytotoxicity of AX gels has not been investigated so far. Therefore, the aim of the present study was to prepare AX-based particles (AXM) by coaxial electrospraying method and to investigate their antioxidant potential and cytotoxicity on human colon cells. Materials and Methods: The gelation of AX was studied by monitoring the storage (G') and loss (G'') moduli. The morphology of AXM was evaluated using optical and scanning electron microscopy (SEM). The in vitro antioxidant activity of AX before and after gelation was measured using the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. In addition, the effect of AX and AXM on the proliferation of human colon cells (CCD 841 CoN) was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: The final G' and G'' values for AX gels were 293 and 0.31 Pa, respectively. AXM presented spherical shape and rough surface with a three-dimensional and porous network. The swelling ratio and mesh size of AXM were 35 g water/g AX and 27 nm, respectively. Gelation decreased the antioxidant activity of AX by 61-64 %. AX and AXM did not affect proliferation or show any toxic effect on the normal human colon cell line CCD 841 CoN. Conclusion: The results indicate that AXM could be promising biocompatible materials with antioxidant activity.
Assuntos
Linhagem Celular/efeitos dos fármacos , Xilanos/metabolismo , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Linhagem Celular/metabolismo , Colo/efeitos dos fármacos , Colo/fisiopatologia , Citotoxinas/farmacologia , Citotoxinas/uso terapêutico , Géis/metabolismo , Géis/uso terapêutico , Humanos , Extratos Vegetais/metabolismo , Extratos Vegetais/uso terapêutico , Xilanos/farmacologiaRESUMO
In this study, the relaxation modulus was used to elucidate the gelling mechanism of polysaccharides from Mesona blumes. The pH of Mesona blumes polysaccharides (MBP) was adjusted could significantly change the relaxation modulus of MBP. The results showed that the hydrogen bonds and electrostatic interaction existed in during the formation of MBP gel. The addition of salt ions (sodium ions and calcium ions), EDTA and urea have different effects on the relaxation modulus of MBP. Result showed that the hydrogen bond was the main force maintaining the MBP gel network structure, followed was calcium ions. And electrostatic interaction was not the decisive role of gel formation. The small molecules with active hydrogen-bond donors and/or acceptors were added into MBP, which proved -COOH was involved in the hydrogen bonds formation of MBP gel. In addition, the entanglement network number (ENN) results quantitatively assessed contribution of interaction: hydrogen bonds interaction > calcium ions (calcium bridge) >electrostatic interaction.
Assuntos
Cálcio/química , Géis/química , Lamiaceae , Extratos Vegetais/química , Polissacarídeos/química , Ureia/química , Cálcio/metabolismo , Relação Dose-Resposta a Droga , Módulo de Elasticidade/fisiologia , Géis/metabolismo , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Polissacarídeos/isolamento & purificação , Polissacarídeos/metabolismo , Reologia/métodos , Ureia/metabolismoRESUMO
Felodipine has a very low bioavailability due to first-pass metabolism. The aim of this study was to enhance its bioavailability by transdermal application. Felodipine-loaded transferosomes were prepared by thin-film hydration using different formulation variables. An optimized formula was designed using statistical experimental design. The independent variables were the used edge activator, its molar ratio to phosphatidylcholine, and presence or absence of cholesterol. The responses were entrapment efficiency of transferosomes, their size, polydispersity index, zeta potential, and percent drug released after 8 h. The optimized formula was subjected to differential scanning calorimetry studies and its stability on storage at 4°C for 6 months was estimated. This formula was improved by incorporation of different permeation enhancers where ex vivo drug flux through mice skin was estimated and the best improved formula was formulated in a gel and lyophilized. The prepared gel was subjected to in vivo study using Plendil® tablets as a reference. According to the calculated desirability, the optimized transferosome formula was that containing sodium deoxycholate as edge activator at 5:1 M ratio to phosphatidylcholine and no cholesterol. The thermograms of this formula indicated the incorporation of felodipine inside the prepared vesicles. None of the tested parameters differed significantly on storage. The lyophilized gel of labrasol-containing formula was chosen for in vivo study. The relative bioavailability of felodipine from the designed gel was 1.7. In conclusion, topically applied lyophilized gel containing felodipine-loaded transferosomes is a promising transdermal delivery system to enhance its bioavailability.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Felodipino/administração & dosagem , Géis/administração & dosagem , Absorção Cutânea/efeitos dos fármacos , Administração Cutânea , Animais , Animais Recém-Nascidos , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Felodipino/química , Felodipino/metabolismo , Liofilização , Géis/química , Géis/metabolismo , Lecitinas/administração & dosagem , Lecitinas/química , Lecitinas/metabolismo , Lipossomos , Camundongos , Absorção Cutânea/fisiologia , Comprimidos , Adesivo TransdérmicoRESUMO
BACKGROUND: Effective micronutrient supplementation strategies are critical to ensure optimal health and productivity in livestock. The objective of this study was to develop a copper and vitamin (multimicronutrient) delivery system based on chitosan gel beads, and test its suitability, in vitro, for use as a cattle feed additive. RESULTS: Chitosan was chelated with copper sulfate to produce millimetre-scale gel matrices (â¼2 mm). The copper content was significantly increased (from 61 to 95 mg g by adjusting pH to alkaline conditions post bead formation. The beads could subsequently be loaded with the model vitamin riboflavin to levels as high as 324 µg g-1 beads. Restricted rehydration of the dried gel matrices in simulated rumen fluid led to a sustained release of riboflavin with no copper released in these neutral conditions for up to 24 h, demonstrating copper rumen bypass. Moreover, sustained release of the mineral was observed in abomasal conditions of pH 2 over a 3 h period. CONCLUSIONS: The matrices showed rumen bypass for copper yet supplied nutritionally relevant levels of the free mineral in abomasal conditions, as required for effective supplementation in cattle. The controlled-release properties demonstrated by the matrices indicate their potential as a multimicronutrient functional feed additive to enhance cattle nutrition and productivity. © 2018 Society of Chemical Industry.
Assuntos
Ração Animal/análise , Bovinos/metabolismo , Quitosana/química , Cobre/química , Sistemas de Liberação de Medicamentos/métodos , Micronutrientes/química , Vitaminas/química , Animais , Cobre/metabolismo , Suplementos Nutricionais/análise , Géis/química , Géis/metabolismo , Micronutrientes/metabolismo , Rúmen/metabolismo , Vitaminas/metabolismoRESUMO
When crude oil samples were shaken (200 rpm) in seawater samples from the Arabian Gulf at 30 °C, usually oil-gels were produced spontaneously leaving the water quite clear. The gelators could probably be based on cholesteryl derivatives. Microscopic examination of the established gels revealed nanofibrellar structures similar to those described by earlier workers for artificially synthesized gelators. Communities of bacteria including prosthetic and stalked members as well as oil-degrading bacteria were recorded in such gels. Chemical analysis revealed that 88.5% of the oil entrapped by gelation was biodegraded after 40 days at 30 °C. Individual bacterial species isolated from the oil-gels biodegraded in batch cultures between 17.8 and 33.3% of the oil added at time zero in 12 days at 30 °C. Gelation is a promising approach, not only for clean, physical removal of oil spilled in aquatic habitats, as so far suggested, but also in its effective microbiological biodegradation, as the current study revealed.
Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Géis/metabolismo , Petróleo/metabolismo , Água do Mar/microbiologia , Poluentes Químicos da Água/metabolismo , Água/metabolismo , Humanos , Água do Mar/química , Água/químicaRESUMO
CONTEXT: Boswellic acids (BAs) are isolated from oleo gum of Boswellia serrata and are mainly used as potential anti-inflammatory, hypolipidemic, immunomodulatory, and antitumor agents. Pharmacokinetic investigations of BAs uncover its poor bioavailability through digestive system thus creates a need for improved therapeutic responses which can possibly be achieved by developing formulations through novel delivery system. OBJECTIVE: Present study was conducted to design topical BA-loaded proniosomal gel for the management of inflammatory disorders with enhanced bioavailability. MATERIALS AND METHODS: Nonionic surfactant vesicles were prepared using the coacervation phase separation method. A central composite design was employed to statistically optimize formulation variables using Design-Expert software. Three independent variables were evaluated: amount of surfactant (X1), amount of soya lecithin (X2), and amount of cholesterol (X3). The encapsulation efficiency percentage (Y1) and particle size (Y2) were selected as dependent variables. RESULTS AND DISCUSSION: The optimum formulation (F10) displayed spherical bi-layered vesicles under transmission electron microscopy with optimum particle size of 707.9 nm and high entrapment efficiency as 98.52%. In vitro skin permeation study demonstrated the most sustained release of 84.83 ± 0.153 mg/cm2 in 24 h. Anti-inflammatory activity of the gel showed a significant (p < 0.001) higher percentage inhibition as compared to the marketed gel at the same dose. CONCLUSION: The present study exhibited that BA-loaded proniosomal gel was better in terms of absorption, bioavailability, and release kinetics.
Assuntos
Géis/química , Géis/farmacologia , Lipossomos/química , Triterpenos/química , Triterpenos/farmacologia , Animais , Disponibilidade Biológica , Química Farmacêutica/métodos , Colesterol/química , Sistemas de Liberação de Medicamentos/métodos , Feminino , Géis/metabolismo , Inflamação/tratamento farmacológico , Lecitinas/química , Masculino , Nanopartículas/química , Nanopartículas/metabolismo , Tamanho da Partícula , Ratos , Ratos Wistar , Pele/metabolismo , Solubilidade , Tensoativos/química , Triterpenos/metabolismoRESUMO
OBJECTIVE: The overall objective of this work is to determine the percutaneous absorption of chlorpromazine hydrochloride from pluronic lecithin organogels (PLO gels) and verify the suitability of topically applied chlorpromazine hydrochloride PLO gels for use in hospice patients for relieving symptoms such as vomiting and nausea during the end stages of life. METHODS: PLO gels of chlorpromazine hydrochloride were prepared using isopropyl palmitate (IPP) or ricinoleic acid (RA) as oil phase. In vitro percutaneous absorption of chlorpromazine hydrochloride was assessed through porcine ear and human abdominal skin. Further, the theoretical steady state plasma concentration (Css) of chlorpromazine was calculated from the flux values. RESULTS: The pH, viscosity, and stability of both PLO gels prepared with IPP and RA were comparable. The thixotropic property of RA PLO gel was found to be better than that of IPP PLO gel. The permeation of chlorpromazine hydrochloride was higher from RA PLO gel than from IPP PLO gel and pure drug solution. Theoretical Css of chlorpromazine from pure drug solution, IPP PLO gel and RA PLO gel were found to be 1.05, 1.20, and 1.50 ng/ml, respectively. PLO gels only marginally increased the flux and theoretical Css of chlorpromazine. CONCLUSION: From this study, it is clearly evident that PLO gels fail to achieve required systemic levels of chlorpromazine following topical application. Chlorpromazine PLO gel may not be effective in treating nausea and vomiting for hospice patients with swallowing difficulties.
Assuntos
Clorpromazina/administração & dosagem , Clorpromazina/metabolismo , Géis/administração & dosagem , Géis/metabolismo , Lecitinas/química , Pele/metabolismo , Abdome , Administração Cutânea , Animais , Clorpromazina/química , Sistemas de Liberação de Medicamentos/métodos , Orelha , Géis/química , Humanos , Palmitatos/química , Ácidos Ricinoleicos/química , Absorção Cutânea/fisiologia , Suínos , ViscosidadeRESUMO
The aim of the present study was to evaluate the gel-forming polysaccharide psyllium in the preparation of mucoadhesive patches for the controlled release of chlorhexidine (CHX) to treat pathologies in the oral cavity, using the casting-solvent evaporation technique. A number of different film-forming semi-synthetic polymers, such as sodium carboxymethyl cellulose (SCMC) and hydroxypropylmethyl cellulose (HPMC) were evaluated for comparison. The patch formulations were characterized in terms of drug content, morphology surface, swelling and mucoadhesive properties, microbiology inhibition assay and in vitro release tests. Three ex-vivo testswere carried out using porcine mucosa: an alternative dissolution test using artificial saliva that allows contemporary measurement of dissolution and mucoadhesion, a permeation test through the mucosa and the measurement of mucoadhesion using a Nouy tensile tester, as the maximum force required for the separation of the patch from the mucosa surface. The patches were also examined for determination of the minimum inhibitory concentration in cultures of Escherichia coli and Staphylococcus aureus. All the patches incorporating psyllium were found suitable in terms of external morphology, mucoadhesion and controlled release of the drug: in the presence of psyllium the drug displays prolonged zero-order release related to slower swelling rate of the system.
Assuntos
Adesivos/metabolismo , Clorexidina/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Mucosa Bucal/metabolismo , Polissacarídeos/metabolismo , Psyllium/metabolismo , Adesivos/administração & dosagem , Adesivos/química , Administração Bucal , Animais , Clorexidina/administração & dosagem , Clorexidina/química , Géis/administração & dosagem , Géis/química , Géis/metabolismo , Mucosa Bucal/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Polissacarídeos/administração & dosagem , Polissacarídeos/química , Psyllium/administração & dosagem , Psyllium/química , SuínosRESUMO
Rhamnogalacturonans I are complex pectin polysaccharides extremely variable in structure and properties and widely represented in various sources. The complexity and diversity of the structure of rhamnogalacturonans I are the reasons for the limited information about the properties and supramolecular organization of these polysaccharides, including the relationship between these parameters and the functions of rhamnogalacturonans I in plant cells. In the present work, on the example of rhamnogalacturonan I from flax gelatinous fibers, the ability of this type of pectic polysaccharides to form at physiological concentrations hydrogels with hyperelastic properties was revealed for the first time. According to IR spectroscopy, water molecules are more tightly retained in the gelling rhamnogalacturonan I from flax fiber cell wall in comparison with the non-gelling rhamnogalacturonan I from primary cell wall of potato. With increase in strength of water binding by rhamnogalacturonan I, there is an increase in elastic modulus and decrease in Poisson's ratio of gel formed by this polysaccharide. The model of hyperelastic rhamnogalacturonan I capture by laterally interacting cellulose microfibrils, constructed using the finite element method, confirmed the suitability of rhamnogalacturonan I gel with the established properties for the function in the gelatinous cell wall, allowing consideration of this tissue- and stage-specific pectic polysaccharide as an important factor in creation of gelatinous fiber contractility.
Assuntos
Pectinas/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Elasticidade , Géis/química , Géis/metabolismo , Modelos Químicos , Pectinas/química , Espectrofotometria InfravermelhoRESUMO
We report the molecular recognition for nucleoside triphosphates inside the ligand-modified water-soluble organic-inorganic hybrid gels composed of polyhedral oligomeric silsesquioxane (POSS). The series of ligands were designed to make hydrogen bonds with each nucleobase and introduced into the hybrid gels. From the titration experiments, the binding constants between the ligand inside the gels and nucleosides were evaluated. Accordingly, it was found that the ligands inside the gels can form a stable complex only with the target nucleoside triphosphate which has the complementary pattern of the hydrogen bonds (Ka=G-gel/cytidine triphosphate (CTP), 3.5×10(8)M(-1); U-gel/adenosine triphosphate (ATP), 1.6×10(3)M(-1); A-gel/uridine triphosphate (UTP), 1.9×10(7), respectively). With other nucleoside derivatives which have different numbers of phosphate units or different types of nucleobases, the much weaker interaction was detected. These data indicate that the complex formation only with nucleoside triphosphates should occur inside the hybrid gels, and selective recognition of each nucleoside triphosphate can be accomplished.
Assuntos
Géis/síntese química , Nucleosídeos/química , Fosfatos de Dinucleosídeos/análise , Géis/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Compostos Inorgânicos , Ligantes , Estrutura Molecular , Nucleosídeos/análise , Fenômenos de Química Orgânica , Espectrometria de FluorescênciaRESUMO
The purpose of this study was to develop and evaluate a delivery system comprising a thermosensitive gel for the sustained release of steroidal hormones in fish, over an extended period of time after a single intramuscular (i.m.) injection and for the improved reproductive performance in fish. Controlled delivery systems based on thermosensitive gels are easy to prepare, low cost and high versatility dosage forms, which have been shown to be effective in several animal species for sustained release of hormones. In this work, a thermosensitive gel system based on poloxamer 407 in water:ethanol medium, able to work as a prolonged release carrier for 17ß-estradiol (E2), has been developed. Such a system was able to solubilize the lipophilic E2 and to gel at the required water temperature for fish rearing (20°C). Moreover, the system exhibited the best injection condition at temperatures below 15°C when the system behaved as a low viscosity Newtonian liquid. The thermosensitive gel system was tested in vivo in the fish model, Carassius auratus, and the results compared with a single i.m. injection of E2 dissolved in corn-oil and other relevant control systems not containing E2. The results were particularly interesting, since fish injected with the E2 thermosensitive gel formulation, showed significantly higher levels of the circulating hormone than corn oil-E2 treated animals at 72 and 96h after injection. In addition, the thermogel system was able to sustain the plasma level of E2 for about 11days. The increased plasma levels of E2 were also accompanied by maintained higher values of plasma vitellogenin (VTG), thus suggesting that the thermosensitive polymer based delivery system could prevent rapid hepatic clearance of E2, resulting in prolonged stimulation of estrogen receptor-mediated pathways in goldfish.
Assuntos
Estradiol/sangue , Géis/metabolismo , Modelos Animais , Poloxâmero/metabolismo , Animais , Química Farmacêutica , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Preparações de Ação Retardada/metabolismo , Avaliação Pré-Clínica de Medicamentos/métodos , Estradiol/administração & dosagem , Estradiol/síntese química , Géis/administração & dosagem , Géis/síntese química , Carpa Dourada , Poloxâmero/administração & dosagem , Poloxâmero/química , TemperaturaRESUMO
The purpose of this work was to prepare stable citrus (CF) and apple (AF) pectin aerogels for potential pharmaceutical applications. Different shapes of low ester pectin aerogels were prepared by two fundamental methods of ionic cross-linking. Pectins' spherical and multi-membrane gels were first formed by the diffusion method using 0.2M CaCl2 solution as an ionic cross-linker. The highest specific surface area (593 m(2)/g) that had so far been reported for pectin aerogels was achieved using this method. Monolithic pectin gels were formed by the internal setting method. Pectin gels were further converted into aerogels by supercritical drying using CO2. As surface area/volume is one of the key parameters in controlling drug release, multi-membrane pectin aerogels were further used as drug delivery carriers. Theophylline and nicotinic acid were used as model drugs for the dissolution study. CF aerogels showed more controlled release behaviour than AF pectin aerogels. Moreover a higher release rate (100%) was observed with CF aerogels.
Assuntos
Implantes Absorvíveis , Portadores de Fármacos/síntese química , Géis/síntese química , Pectinas/síntese química , Portadores de Fármacos/metabolismo , Géis/metabolismo , Pectinas/metabolismo , SolubilidadeRESUMO
Conventional carriers for skin delivery encounter obstacles of drug leakage, scanty permeation and low entrapment efficiency. Phospholipid nanogels have recently been recognized as prominent delivery systems to circumvent such obstacles and impart easier application. The current review provides an overview on different types of lecithin nanostructured gels, with particular emphasis on liposomal versus microemulsion gelled systems. Liposomal gels investigated encompassed classic liposomal hydrogel, modified liposomal gels (e.g. Transferosomal, Ethosomal, Pro-liposomal and Phytosomal gels), Microgel in liposomes (M-i-L) and Vesicular phospholipid gel (VPG). Microemulsion gelled systems encompassed Lecithin microemulsion-based organogels (LMBGs), Pluronic lecithin organogels (PLOs) and Lecithin-stabilized microemulsion-based hydrogels. All systems were reviewed regarding matrix composition, state of art, characterization and updated applications. Different classes of lecithin nanogels exhibited crucial impact on transdermal delivery regarding drug permeation, drug loading and stability aspects. Future perspectives of this theme issue are discussed based on current laboratory studies.
Assuntos
Géis/metabolismo , Lecitinas/química , Lipossomos/química , Pele/metabolismo , Administração Cutânea , Animais , Emulsões/química , Emulsões/metabolismo , Géis/química , Humanos , Lecitinas/metabolismo , Lipossomos/metabolismo , Lipossomos/ultraestrutura , Nanoestruturas/química , Nanoestruturas/ultraestruturaRESUMO
OBJECTIVE: Tamoxifen (TAM) is widely employed in the treatment of breast malignancies and is also found to be effective in psoriasis treatment. The current studies aimed to explore the antipsoriatic potential of topical TAM encapsulated in the new generation phospholipid-based vesicular and micellar systems, i.e. flexible membrane vesicles (FMVs) and pluronic lecithinized organogels (PLOs). METHODS: TAM-loaded-FMVs were prepared by thin-film hydration technique, while TAM-PLOs were prepared by simple mixing. Mouse-tail model was used to evaluate the antipsoriatic activity of the novel formulations. The mouse tails were treated once-a-day with different formulations for a period of four weeks and prepared for longitudinal histological sections by hematoxylin-eosin staining technique. The length of the orthokeratotic regions in stratum granulosum was measured on 10 sequential scales per tail section as percentage of the full length of the scale, and the drug activity was calculated further. RESULTS: Evaluation of antipsoriatic activity on mice tail revealed significantly higher (p < 0.01) efficacy of TAM-FMV gel (i.e. 35.8%) and TAM-PLO (i.e. 24.6%) vis-à-vis the conventional TAM-hydrogel (i.e. 10.2%). CONCLUSIONS: The results of these studies demonstrated immense potential of the topically applied TAM-encapsulated vesicular and micellar systems in psoriasis, thus calling for more comprehensive investigations to establish the role of TAM in the management of psoriasis.