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1.
An. acad. bras. ciênc ; 89(1,supl): 745-755, May. 2017. tab, graf
Article in English | LILACS | ID: biblio-886671

ABSTRACT

ABSTRACT Enzymatically crossliked gelatin hydrogel was submitted to two different drying methods: air drying and freeze drying. The resulting polymeric tridimensional arrangement (compact or porous, respectively) led to different thermal and swelling properties. Significant differences (p < 0.05) on thermal and mechanical characteristics as well as swelling in non-enzymatic gastric and intestinal simulated fluids (37 ºC) were detected. Water absorption data in such media was modelled according to Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin equations. Freeze dried hydrogel showed Fickian diffusion behavior while air dried hydrogels presented poor adjustment to Higuchi model suggesting the importance of the relaxation mechanism at the beginning of swelling process. It was possible to conclude that the same gelatin hydrogel may be suitable to different applications depending on the drying process used.


Subject(s)
Water , Hydrogels/metabolism , Freeze Drying , Gelatin/metabolism , Time Factors , Calorimetry, Differential Scanning , Microscopy, Electron, Scanning , Hydrogels/chemistry , Mechanical Phenomena , Gelatin/ultrastructure , Gelatin/chemistry
2.
s.l; s.n; s.n; dez. 2015. 184 p. ilus, tab, graf.
Thesis in Portuguese | LILACS | ID: biblio-834049

ABSTRACT

A associação de filtros solares a compostos bioativos tem sido estudada com ênfase na última década. Contudo, a solubilidade limitada dos compostos naturais, tais como a rutina, restringe o desenvolvimento de preparações cosméticas seguras, funcionais e estáveis. A proposta deste estudo envolveu a obtenção de nanoestruturas de gelatina (contendo ou não rutina) para aplicação em protetores solares. Os objetivos específicos foram: (1) preparar partículas de gelatina; (2) realizar a caracterização física, físico-química, morfológica, térmica e funcional (in vitro); (3) avaliar a citotoxicidade e a penetração/permeação curtânea in vitro dos sistemas; (4) desenvolver fotoprotetores bioativos de eficácia estimada in vitro; e (5) determinar a segurança e eficácia clínica fotoprotetora das preparações contendo as estruturas proteicas. As nanopartículas apresentaram-se esféricas e com diâmetro médio e índice de polidispersividade variando entre 318,9 ± 6,9 (B-NC) a 442,8 ± 4,9 nm (R-NC) e 0,06 ± 0,03 (B-NC) a 0,12 ± 0,01 (R-NC), respectivamente. Os valores do potencial zeta apresentaram-se entre -28,5 ± 0,9 mV (B-NC) e -26,6 ± 0,5 mV (R-NC). R-NC apresentou eficiência de associação equivalente a 51,8 ± 1,4%. Os ensaios de segurança das nanopartículas evidenciaram perfil citotóxico adequado para aplicação cosmética, bem como, a ausente tendência de penetração/permeação cutânea. Tendo em vista os resultados obtidos in vitro, as nanopartículas contendo rutina apresentaram capacidade antioxidante 74% superior à rutina em seu estado livre e contribuíram para o aumento de 48% do fator de proteção solar (FPS) quando associada à avobenzona (butyl methoxydibenzoylmethane), ao p-metoxicinamato de octila (ethylhexyl methoxycinnamate) e ao octil dimetil PABA (ethylhexyl dimethyl PABA). A avaliação da eficácia clínica das formulações evidenciou a influência da nanopartícula, sem adição do flavonoide, na proteção da pele contra a formação do eritema UV induzido. Por meio da avaliação dos aspectos funcionais, foi possível constatar, in vitro e in vivo, que a adição das nanopartículas em sistemas fotoprotetores influenciou seu perfil de transmitância da radiação UV, bem como, seus efeitos sobre o eritema UV induzido. Os resultados obtidos apresentaram perspectivas de aplicação prática no desenvolvimento de produtos cosméticos fotoprotetores associados a substâncias bioativas, por meio de plataforma nanotecnológica


Especially, in the last decade, the association of chemical filters and bioactive compounds has been studied by several authors. However, the limited solubility of natural compounds, such as rutin restricts the development of safe and stable cosmetic preparations. The aim of this work was the development of gelatin nanoparticles (with or without rutin) as an ingredient in sunscreens. The specific goals were: (1) the development of rutin-loaded gelatin nanoparticles; (2) to perform the physical, physical-chemical, morphological, thermal and functional (in vitro) analysis; (3) to assess the cytotoxicity and skin penetration / permeation in vitro of the nanoparticles; (4) to develop bioactive sunscreens and to perform the in vitro photoprotection efficacy assay; and (5) to evaluate the in vivo sun protection factor (SPF) of the formulations. The nanoparticles were spherical with an average size and polydispersive index between 318.9 ± 6.9 nm (B-NC) at 442.8 nm ± 4.9 (R-NC), and 0.06 ± 0, 03 (B-NC) to 0.12 ± 0.01 (R-NC). The zeta potential values were high and negative, ranging from - 28.5 ± 0.9 mV (B-NC) and -26.6 ± 0.5 mV (R-NC). R-NC entrapment efficient was 51.8 ± 1.4%. The nanoparticle safety assessment showed a cytotoxic profile suitable for cosmetic application, as well as the absent trend of penetration/ permeation of the skin. The in vitro results indicated that the rutin-loaded gelatin nanoparticles increased 74% the antioxidant profile in comparison with free rutin and also increased 48% the SPF (in vitro) when combined with butyl methoxydibenzoylmethane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl PABA. The assessment of the clinical efficacy assays showed the influence of blank nanoparticle in the protection of the skin against UV-induced erythema response. It was established in vitro and in vivo that the addition of gelatin nanoparticles in sunscreens influenced its UV transmittance profile, as well as its anti-erythema effects on the skin. The results have practical application in the development of sunscreen with bioactive ingredients and at the design of an innovative ingredient with a chemopreventive profile


Subject(s)
Gelatin/chemistry , Nanotechnology , Sunscreening Agents/analysis , Cosmetics , Nanoparticles/analysis , Rutin/chemistry
3.
Article in English | WPRIM | ID: wpr-157422

ABSTRACT

OBJECTIVE: To retrospectively compare treatment of hepatocellular carcinoma (HCC) with transarterial chemoembolization (TACE) using gelatin sponges or microspheres plus lipiodol-doxorubicin vs. doxorubicin-loaded drug-eluting beads (DEB). MATERIALS AND METHODS: A total of 158 patients with HCC received TACE from November 2010 to November 2011 were enrolled in this study, including 64 (40.5%) received TACE with lipiodol-doxorubicin and gelatin sponges (group A), 41 (25.9%) received TACE with lipiodol-doxorubicin and microspheres (group B), and 53 (33.5%) received TACE with doxorubicin-loaded DEB (group C). Tumor response and adverse events (AEs) were evaluated. RESULTS: No significant difference was found at baseline among the three groups. The doxorubicin dosage in group C was significantly (p < 0.001) higher compared to the dose used in groups A or B (median, 50 mg vs. 31 mg or 25 mg). Significantly (p < 0.001) more patients in group C achieved complete response compared to those in groups A or B (32.1% vs. 6.3% or 2.4%). Significantly (p < 0.001) less patients in group C had progressive disease compared to those in groups A or B (34.0% vs. 57.8% or 68.3%). Minor AEs were more common in groups A and B compared to group C, with rates of 54.7%, 34.1%, and 5.7%, respectively. CONCLUSION: In patients with HCC, TACE with DEB offers better safety and efficacy profiles compared to either TACE with gelatin sponges or TACE with microspheres.


Subject(s)
Abdominal Pain/etiology , Adult , Aged , Antibiotics, Antineoplastic/administration & dosage , Carcinoma, Hepatocellular/drug therapy , Chemoembolization, Therapeutic , Disease-Free Survival , Doxorubicin/administration & dosage , Drug Carriers/chemistry , Ethiodized Oil/chemistry , Female , Fever/etiology , Follow-Up Studies , Gelatin/chemistry , Humans , Kaplan-Meier Estimate , Liver Neoplasms/drug therapy , Male , Microspheres , Middle Aged , Retrospective Studies
4.
Indian J Biochem Biophys ; 2011 Feb; 48(1): 29-34
Article in English | IMSEAR | ID: sea-135297

ABSTRACT

Bacterial organophosphate hydrolases (OPH) have been shown to hydrolyze structurally diverse group of organophosphate (OP) compounds and nerve agents. Due to broad substrate range and unusual catalytic properties, the OPH has successfully been used to develop eco-friendly strategies for detection and decontamination of OP compounds. However, their usage has failed to gain necessary acceptance, due to short half-life of the enzyme and loss of activity during process development. In the present study, we report a simple procedure for immobilization of OPH on biocompatible gelatin pads. The covalent coupling of OPH using glutaraldehyde spacer has been found to dramatically improve the enzyme stability. There is no apparent loss of OPH activity in OPH-gelatin pads stored at room temperature for more than six months. As revealed by a number of kinetic parameters, the catalytic properties of immobilized enzyme are found to be comparable to the free enzyme. Further, the OPH‑gelatin pads effectively eliminate OP insecticide methyl parathion and nerve agent sarin.


Subject(s)
Enzyme Stability , Enzymes, Immobilized/chemistry , Escherichia coli/enzymology , Escherichia coli/genetics , Gelatin/chemistry , Hydrolysis , Insecticides/poisoning , Methyl Parathion/chemistry , Organophosphorus Compounds/chemistry , Phosphoric Monoester Hydrolases/genetics , Phosphoric Monoester Hydrolases/isolation & purification , Phosphoric Monoester Hydrolases/metabolism , Sarin/chemistry , Substrate Specificity
5.
Electron. j. biotechnol ; 13(5): 20-21, Sept. 2010. ilus, tab
Article in English | LILACS | ID: lil-591902

ABSTRACT

Gelatin, chitosan and hyaluronic acid are natural components used to prepare polymeric scaffold in tissue engineering. The physical properties of these materials confer an appropriate microenvironment for cells, which can be used as a regeneration system for skin and cartilage. In this work, we prepared and characterized a Gelatin/Chitosan/Hyaluronan lyophilized-polymer. Physical properties of lyophilized-polymer changed slightly with moisture, but when polymer was totally hydrated the elasticity changed significantly. Thermophysical characterisation indicated that temperatures higher than 30ºC could modify irreversibly the polymeric matrix probably due to protein denaturation. Besides, we used the polymer as scaffold to prepare a biosynthetic-skin, reporting biological behaviour and its mechanical properties.


Subject(s)
Hyaluronic Acid/chemistry , Gelatin/chemistry , Chitosan/chemistry , Calorimetry, Differential Scanning , Immunohistochemistry , Microscopy, Electron, Scanning , Biocompatible Materials/chemistry , Polymers , Skin, Artificial
6.
Indian J Exp Biol ; 2001 Sep; 39(9): 902-5
Article in English | IMSEAR | ID: sea-58625

ABSTRACT

Implants of chloroquine phosphate (CQP) using biodegradable polymer, gelatin (G) and cross-linked gelatin (CLG) were prepared and evaluated to assess their physicochemical properties and in vitro release profile. The mechanism and kinetics of release were studied to correlate the release phenomenon with the formulation parameters. Out of many batches of the implants investigated, the implant prepared with 20% gelatin at 2:1 drug polymer ratio, 10% crosslinking agent and 2% plasticizer (Batch J) was found to provide optimum release behavior conforming to the requirements of a long term implant for a week. In vivo studies conducted on albino rats showed consistent therapeutic blood level over a period of 7 days. Mean residence time (MRT) of the drug released in the body, calculated as the ratio of the area under the first moment curve (AUMC) to area under concentration time curve (AUC) was 72 hr for implant against 2.42 hr for subcutaneous injection.


Subject(s)
Animals , Antimalarials/administration & dosage , Chemoprevention , Chloroquine/administration & dosage , Dose-Response Relationship, Drug , Drug Implants , Female , Gelatin/chemistry , Malaria, Falciparum/drug therapy , Male , Plasmodium falciparum , Rats
7.
Indian J Biochem Biophys ; 1997 Oct; 34(5): 449-60
Article in English | IMSEAR | ID: sea-26412

ABSTRACT

Extent of water vapour adsorption (n1) of gelatin and bovine serum albumin and their mixtures in different proportion respectively has been measured by isopiestic vapour pressure methods at various values of water activity (a1) ranging between zero and unity. Similar measurements have also been carried out with gelatin and BSA coated alumina powder. At a given value of a1, n1 for the protein mixture is found to be significantly less than their ideal value obtained from the additivity rule. Such decrease is probably due to the protein-protein interaction as a result of which some of the water binding sites become unavailable for water vapour adsorption. On the other hand when a protein is mixed with alumina powder, the water vapour adsorption of the protein coated alumina surface at a given water activity is found to be 2 to 3 times larger than its ideal value obtained from the additivity rule. The standard free energy changes for hydration of protein mixtures and protein-coated alumina have been evaluated using Bull equation. The extent of excess hydration of these proteins and their mixtures as well as protein-coated alumina in the presence of excess neutral salts and urea respectively have been evaluated using the isopiestic method. In all cases, the moles of water and solute respectively bound in absolute amount to biopolymers, biopolymer mixtures and protein-coated alumina have been evaluated in the limited range of solute concentrations in the medium. Based on the Gibbs-Duhem equations, a rigorous expression for the standard free energy change for binding of excess solute and solvent to biopolymer have been evaluated with reference to unit solute mole fraction as standard state. Free energies of excess hydration of different biopolymer systems have been evaluated using this equation.


Subject(s)
Aluminum Oxide/chemistry , Gelatin/chemistry , Protein Binding , Serum Albumin, Bovine/chemistry , Surface Properties , Water/chemistry
8.
Indian J Biochem Biophys ; 1996 Feb; 33(1): 39-47
Article in English | IMSEAR | ID: sea-28398

ABSTRACT

The kinetics of adsorption of soluble denatured protein, gelatin has been studied at the alumina-water interface as a function of protein concentration, pH, temperature and ionic strength. The rate of adsorption of gelatin has been compared with rate of adsorption of BSA denatured by 8 M urea or 0.05 M SDS. The initial stage for the adsorption process is diffusion-controlled and the surface diffusion coefficients evaluated from equations of Ward and Tordai and by Bull for globular and denatured proteins are found to be widely different from each other. The kinetic data for gelatin fit into a first order rate equation with two rate constants, k1a and k2a. Using Arrhenius equation, the activation energies delta E1* and delta E2* have been evaluated from the values of k1a and k2a respectively. The corresponding changes in values of enthalpy of activation (delta H*), entropy of activation (delta S*) and free energy of activation (delta G*) have been evaluated using Eyring's equation for absolute reaction rate. It has been found that for both gelatin and denatured BSA, in the first kinetic step delta H1* > T delta S1* and for the second step T delta S2* > delta H2.


Subject(s)
Adsorption , Aluminum Oxide , Gelatin/chemistry , Kinetics , Protein Denaturation , Serum Albumin, Bovine/chemistry , Thermodynamics , Water
9.
Indian J Biochem Biophys ; 1993 Oct; 30(5): 297-305
Article in English | IMSEAR | ID: sea-27100

ABSTRACT

The pH titration of nine amino acids (glycine, proline, valine, serine, glutamine, tryptophan, arginine, histidine and aspartic acid) in presence of urea in the concentration range 1-8 mole dm-3 has been performed. The results support suppression of the first dissociation constant (K1) of the amino acids and acceptance of H+ ions by the amide forming uronium ion (UH+). The second dissociation constant (K2) of the amino acids is affected relatively weakly by urea. Quantitative evaluation of different species existing in solution and the degree of dissociation of the acids as well as the degree of binding of H+ ion to the amide have been made. It has been found that the polarity of the aqueous-urea medium does not straight forwardly correlate with the altered pK1 of the amino acids. Urea can also affect the pH-titration behaviour of gelatin with an increase of the intrinsic pK of the acidic groups of the protein by 0.45 unit.


Subject(s)
Amino Acids/chemistry , Gelatin/chemistry , Hydrogen-Ion Concentration , Kinetics , Mathematics , Protein Binding , Urea/chemistry
10.
Indian J Biochem Biophys ; 1991 Apr; 28(2): 114-23
Article in English | IMSEAR | ID: sea-26823

ABSTRACT

Extent of adsorption (gamma pw) of bovine serum albumin, beta-lactoglobulin, gelatin and myosin at the alumina-water interface has been measured as function of protein concentration (Cp) at several temperatures, pH, and ionic strengths of the medium. gamma pw for proteins in most cases increases with increase of protein concentration but it attains maximum value gamma pw(m) when Cp is high. Values of maximum adsorption have been examined in terms of molecular orientation, molecular size and shape and unfolding of the packed proteins at the interface. In few cases, gamma pw increases with increase of Cp without reaching a real state of saturation as a result of aggregation of molecules or extensive unfolding of the protein at the interface. In the case of beta-lactoglobulin at pH 5.2 and ionic strength 0.05, gamma pw in high concentration region decreases to zero value when Cp increases. For myosin at 45 degrees C and pH 6.4, and also at 27 degrees and pH 7.8, the values of gamma pw are all negative and these negative values increase with increase of Cp. All these results have been explained in terms of significant competitions of water and protein for binding to the surface sites of the powdered alumina. Adsorption of myosin has also been found to be affected in the presence of NaCl, KCl, CaCl2, KI, Na2SO4, LiCl and urea. The relative affinities of the adsorption of various proteins for the surface of alumina at different physical conditions of the system have been compared in terms of maximum values of adsorption attained when gamma pw is varied with Cp. The affinities are shown to be compared more precisely in terms of the standard free energy decrease for the saturation of the surface by protein as a result of the change in its concentration from zero to unity in the mole fraction scale.


Subject(s)
Adsorption , Aluminum Oxide , Gelatin/chemistry , Lactoglobulins/chemistry , Myosins/chemistry , Proteins/chemistry , Serum Albumin, Bovine/chemistry , Thermodynamics
11.
Indian J Biochem Biophys ; 1991 Apr; 28(2): 124-32
Article in English | IMSEAR | ID: sea-28356

ABSTRACT

Extent of adsorption of proteins at alumina-water interface from solutions containing binary mixture of beta-lactoglobulin and bovine serum albumin (BSA), beta-lactoglobulin and gelatin, and gelatin and bovine serum albumin has been estimated as functions of protein concentrations at varying pH, ionic strength, temperature and weight fraction ratios of protein mixture. The extent of adsorption (gamma lacw) of lactoglobulin in the presence of BSA increases with increase of protein concentration (Clac) until it reaches a maximum but a fixed value gamma lacw(m). Extent of adsorption gamma serw also initially increases with increase of protein concentrations until it reaches maximum value gamma serw(m). Beyond these protein concentrations, adsorbed BSA is gradually desorbed due to the preferential adsorption of lactoglobulin from the protein mixture. In many systems, gamma serw at high protein concentrations even becomes negative due to the strong competition of BSA and water for binding to the surface sites in the presence of lactoglobulin. For lactoglobulin-gelatin mixtures, adsorption of both proteins is enhanced as protein concentration is increased until limiting values for adsorption are reached. Beyond the limiting value, lactoglobulin is further accumulated at the interface without limit when protein concentration is high. For gelatin-albumin mixtures, extent of gelatin adsorption increases with increase in the adsorption of BSA. The limit for saturation of adsorption for gelatin is not reached for many systems. At acid pH, adsorbed BSA appears to be desorbed from the surface in the presence of gelatin. From the results thus obtained the role of electrostatic and hydrophobic effects in controlling the adsorption process has been analysed.


Subject(s)
Adsorption , Aluminum Oxide , Gelatin/chemistry , Lactoglobulins/chemistry , Proteins/chemistry , Serum Albumin, Bovine/chemistry
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