Hydrogel-elastomer composite biomaterials: 2. Effects of aging methacrylated gelatin solutions on the preparation and physical properties of interpenetrating polymer networks

This study was conducted to understand the effects of aging methacrylated gelatin solutions on the properties of gelatin-HydroThane^TM Interpenetrating Polymer Network (IPN) films. The latter were prepared from methacrylated gelatin solutions that were either freshly made or stored at different concentrations and temperatures for various periods. The morphology, swelling stability and mechanical properties of the IPNs were then accordingly characterized. The IPNs prepared with aged solutions showed a reduced phase separation; changed from a network-like structure to a continuous phase structure; and demonstrated higher swelling stabilities and higher elasticity under optimal aging conditions, compared to the IPN prepared with a fresh methacrylated gelatin solution. An increase in viscosity and a change in phase transition of aged methacrylated gelatin solutions were also observed, presumably due to the physical structuring of methacrylated gelatin chains (e.g., by the formation of a helix structure), thus altering the resulting IPN characteristics. A better understanding of the effects of aging methacrylated gelatin solution on the formation and properties of gelatin-HydroThane^TM IPNs should enable us to further develop our composite biomaterials for different dressing applications.     

Evaluation and Comparison of Physicomechanical Characteristics of Gelatin and Hypromellose Capsules

ABSTRACT

The aim of this study is evaluation and comparison of physical and mechanical properties of hypromellose and gelatin capsules. For this purpose, the empty and filled capsules of hypromellose and gelatin (size 4) were examined in regard with their physical and mechanical characteristics, employing textural analysis, and disintegration properties in various immersion fluids, utilizing a USP 28 disintegration apparatus. The results demonstrated that owing to their greater water permeability, gelatin capsules disintegrate much faster than hypromellose shells in all tested media. However, hypromellose capsules showed a more uniform pattern of dispersion in the disintegration fluids. As for mechanical properties, at ambient conditions, gelatin capsules appeared to be harder and stronger with less elasticity as compared with hypromellose shells. On the contrary, at an elevated temperature, gelatin capsules demonstrated lower resilience. This study shows that hypromellose capsules have excellent properties and are promising as far as regulatory, manufacturing, religious, and dietary issues are concerned.     

Development of chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis

The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH?=?7.4) containing 10⁴?U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications.     

The properties of gelatin film‐neem extract and its effectiveness for preserving minced beef

The properties of gelatin films developed from neem extract (NE; Azadirachta indica) were determined. Moreover, the developed films were applied to minced beef to test its effectiveness for preserving the meat. The quality attributes of the minced beef wrapped with the developed film were monitored over a 7‐day period in refrigerated storage (4 ± 1°C) and were compared to a control commercial wrap film (polyvinyl chloride). The addition of NE improved the elongation at break, solubility, and antioxidant activity of the gelatin films. After 7 days of storage, the minced beef wrapped with the experimental film showed the highest a* and weight loss values. Gradually, changes in TBARS were more pronounced in the experimental sample. It was concluded that gelatin film containing NE is a potentially promising film that could help delay oxidative reactions. However, some characteristics of the film (eg, mechanical properties and water vapor permeability) need to be improved before putting them to commercial use.     

Relationship Between film Properties and Drug Release from Acrylic Films

Abstract

An in vitro technique was used to determine the release rates of drugs from different acrylic copolymers as carrier systems. The drugs used in this investigation were pilocarpine, streptomycine, isosorbide salts and nitroglycerol. By applying the Higuchi equations the diffusion coefficients of the drugs were calculated. A tensile stress test was used to examine certain mechanical properties of the films.

It was found that the incorporation of drugs into acrylic films by different techniques allowed the facile preparation of various compositions with diffusion coefficients in a relativly large range (10^-8…10^-15cm² s^-1). The choice of the physicochemical state of the drug and the film composition can significantly affect drug release. The strain of the films depended on the tensile stress, the water and additives content.

It was examined that the drug release depended on the mechanical properties of the films. In general the drug release was faster from the lower viscosity grades and higher humidity contents of the films. This can be done by modifying the chemical structure of the used polymer system or by making use additives with alcoholic groups.     

明胶-壳聚糖复合膜的制备与性能

制备了一系列不同配比的明胶-壳聚糖复合膜,研究了壳聚糖含量对复合膜力学性能、吸湿性能的影响,通过X射线衍射和红外光谱分析了复合膜的结构。结果表明,复合膜及纯壳聚糖膜的断裂伸长率和拉伸强度均大于纯明胶膜,壳聚糖的加入可改善膜的力学性能。随壳聚糖含量的增加,复合膜的吸湿率增大。明胶与壳聚糖分子间存在较强的相互作用,与明胶共...     

花青素-明胶/聚乙烯醇-淀粉复合膜制备与表征

目的 制备花青素明胶/聚乙烯醇淀粉双层复合膜,以期提高花青素单层膜的综合性能.方法 采用流延法分别制备紫薯、紫甘蓝、黑米、黑枸杞、玫瑰、玫瑰茄等6种花青素明胶/聚乙烯醇淀粉双层复合膜,并对比研究膜层的微观组织结构、含水率、力学性能及光学性能.结果 从红外光谱图中可以看出,双层复合膜分子结构没有出现新的特征峰,双层膜结合方式为物理结合,没有新的结构生成,且除紫甘蓝明胶/聚乙烯醇淀粉双层复合膜外,其余复合膜均存在明显的分层界线,2层结合处膜层结构均匀致密,结合良好.不同双层膜的含水率差异显著,而双层复合膜比花青素单层膜的含水率明显降低,不同双层膜的拉伸强度和断裂伸长率差异不显著,与单层花青素明胶复合膜相比,双层复合膜的拉伸强度和断裂伸长率大幅增加,其中紫薯双层膜的拉伸强度增加了75％,断裂伸长率增加了22.9％;所有双层复合膜的透光率相差不大,均在80％以上;与花青素明胶单层膜相比,双层膜的雾度增加了20％左右.结论 制备的双层膜改善了单层膜的力学性能,提高了花青素明胶单层膜的综合性能.     

The Influence of Pre-treatment on the Properties of Photographic Gelatin

Abstract

The influence of the liming period in the manufacturing process on the chemical and photographic properties of gelatin was investigated. Three limed osseins soaked for various periods were prepared and gelatins zvere extracted from them. The impurity contents of the gelatins and the physical restraining properties decreased with prolonging liming periods. The impurity contents and physical retardance were also relative to the extraction order. The deionization treatment of gelatin decreased the impurity contents and the differences of restraining effect with extraction order. Furthermore, the fractionation of sample gelatins by use of gel permeation chromatography was applied to study the relationship to the molecular weight of impurity contents and amino acid composition, as affected by the liming period.     

Combinatorial investigation of Fe–B thin-film nanocomposites

Abstract

Combinatorial magnetron sputter deposition from elemental targets was used to create Fe–B composition spread type thin film materials libraries on thermally oxidized 4-in. Si wafers. The materials libraries consisting of wedge-type multilayer thin films were annealed at 500 or 700 °C to transform the multilayers into multiphase alloys. The libraries were characterized by nuclear reaction analysis, Rutherford backscattering, nanoindentation, vibrating sample magnetometry, x-ray diffraction (XRD) and transmission electron microscopy (TEM). Young's modulus and hardness values were related to the annealing parameters, structure and composition of the films. The magnetic properties of the films were improved by annealing in a H₂ atmosphere, showing a more than tenfold decrease in the coercive field values in comparison to those of the vacuum-annealed films. The hardness values increased from 8 to 18 GPa when the annealing temperature was increased from 500 to 700 °C. The appearance of Fe₂B phases, as revealed by XRD and TEM, had a significant effect on the mechanical properties of the films.     

明胶/海藻酸钠(京尼平交联)互穿网络膜的制备与性能

为了提高海藻酸钠与明胶各自的性能,首先,以海藻酸钠和明胶为原料,以京尼平、CaCl2为交联剂,采用分步交联法制备了明胶/海藻酸钠互穿网络膜。然后,利用FTIR对明胶/海藻酸钠互穿网络结构进行了表征与分析,根据FTIR结果推测了互穿网络结构形成的机制。最后,探讨了京尼平的加入量和明胶与京尼平的质量比对互穿网络膜力学性能和交联度的影响,及海藻酸钠与明胶的质量比对互穿网络膜力学性能、断面形貌、热稳定性和吸水保水性能的影响。结果表明:当明胶与京尼平的质量比为200∶1、海藻酸钠与明胶的质量比为2∶1时,互穿网络膜具有最佳的力学性能、吸水保水性能和相容性;此外,互穿网络膜的力学性能也优于纯海藻酸钠膜与纯明胶膜的。明胶的加入提高了互穿网络膜在低温区的热稳定性,但降低了高温区的热稳定性。海藻酸钠与明胶之间可能以分子间作用力、氢键及离子键等相互作用,提高了二者各自的初始分解温度与最大热分解温度。研究解决了海藻酸钠与明胶力学性能差的问题,为拓展海藻酸钠在医用领域的应用提供参考。     

Change in the Molecular Weight Distribution of Gelatin by a High Pressure Slurry Jet

Abstract

Physical and photographic properties of gelatin depend on the molecular weight distribution of the gelatin, which it is important to control. We controlled the molecular weight distribution of gelatin by pressurizing the sample gelatin solution and jetting it at high velocity from a nozzle to a collision plate. II was found that this method teas effective in controlling the molecular weight distribution of gelatin and in preparing a gelatin which contains mainly ± and β components and few high and low molecular weight components.     

Preparation of reduced graphene oxide/gelatin composite films with reinforced mechanical strength

Graphene oxide (GO) was reduced by chitosan/gelatin solution and added to gelatin (Gel) to fabricate reduced graphene oxide/gelatin (RGO/Gel) films by a solvent-casting method using genipin as cross-linking agent. The structure and properties of the films were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and UV–vis spectroscopy. The addition of RGO increased the tensile strength of the RGO/Gel films in both dry and wet states, but decreased their elongation at break. The incorperation of RGO also decreased the swelling ability of the films in water. Cell cultures were carried out in order to test the cytotoxicity of the films. The cells grew and reproduced well on the RGO/Gel films, indicating that the addition of RGO has no negative effect on the compatibility of the gelatin. Therefore, the reduced graphene oxide/gelatin composite is a promising biomaterial with excellent mechanical properties and good cell compatibility.     

可食性明胶-魔芋葡甘聚糖共混膜的制备与性能研究

采用溶液共混法制备了一系列不同比例的明胶-魔芋葡甘聚糖共混膜,研究了明胶含量(质量分数)对共混膜的力学性能、吸湿性能、透光性能的影响。结果表明,明胶的引入,有利于改善魔芋葡甘聚糖膜的力学性能,减小魔芋葡甘聚糖膜的吸水率,明胶与魔芋葡甘聚糖的相容性良好。     

Hydrogel-elastomer composite biomaterials: 3. Effects of gelatin molecular weight and type on the preparation and physical properties of interpenetrating polymer networks

To optimize the preparation of a gelatin-HydroThane^TM Interpenetrating Polymer Network (IPN) and obtain optimum physical properties for its use as a wound dressing, we studied IPN films prepared with two types of gelatin having different molecular weights. The effects of the gelatin molecular weight and type on the IPN film’s structure, morphology, swelling and mechanical properties were determined. While FTIR did not reveal any noticeable differences between the IPNs prepared using different gelatin, light microscopy showed a lesser phase separation of the film prepared with a high-molecular-weight type A gelatin. Furthermore, these films displayed slightly less swelling, higher strength and lower strain, compared to the IPNs prepared with either low-molecular-weight type A or type B gelatin. The IPN prepared with type B gelatin showed higher swelling in serum-containing medium than those prepared with type A gelatin, because of its ionic charges under the condition. Increases in viscosity were observed with increasing molecular weight, type A being more viscous than type B gelatin despite having a lower bloom number. The viscosity of the high-molecular-weight gelatin was in the same magnitude as that of HydroThane^TM, which might lead to less phase separation. A better understanding of the effects of alterations in the gelatin molecular weight and type on the formation and properties of the gelatin-HydroThane^TM IPN should facilitate the development of promising composite biomaterials for wound dressing applications.     

Interactions between Adsorbed Gelatin Layers

Abstract

The interaction energies between gelatin coated surfaces at various electrolyte and pH conditions have been determined and are reported. These experiments were performed by attaching a small glass sphere to an AFM tip, allowing the gelatin to adsorb, and then moving the AFM tip toward an optically flat surface. The importance of adsorption conditions as well as the current conditions are discussed. A number of general trends have been observed. The layer was seen to expand with increasing pH. At low pH the surfaces are negative and the gelatin positive and thus the polyampholyte tends to lay relatively flat. As the pH is increased the strong interaction between the surface and polyampholyte decreases and so the gelatin extends away from the surface. On changing electrolyte concentration, no effect was seen at the isoelectric point, however, the layer was observed to swell at more alkaline pHs.

By oscillating the AFM tip as the surfaces are moved together and determining the response of the tip to the oscillation, some mechanical properties of the gelatin may be obtained. In particular, the viscoelastic properties may be determined from the amplitude of oscillation and the phase lag of the response. The results show that when the adsorbed gelatin layers interact, the response changes from being primarily viscous to primarily elastic in nature and as the adsorbed layers are compressed further an almost entirely elastic response is noted.     

Development and characterization of a mucoadhesive sublingual formulation for pain control: extemporaneous oxycodone films in personalized therapy

Objective: The aim of this work was the development of mucoadhesive sublingual films, prepared using a casting method, for the administration of oxycodone.

Materials and methods: A solvent casting method was employed to prepare the mucoadhesive films. A calibrated pipette was used to deposit single aliquots of different polymeric solutions on a polystyrene plate lid. Among the various tested polymers, hydroxypropylcellulose at low and medium molecular weight (HPC) and pectin at two different degrees of esterification (PC) were chosen for preparing solutions with good casting properties, capable of producing films suitable for mucosal application.

Results and discussion: The obtained films showed excellent drug content uniformity and stability and rapid drug release, which, at 8?min, ranged from 60% to 80%. All films presented satisfactory mucoadhesive and mechanical properties, also confirmed by a test on healthy volunteers, who did not experience irritation or mucosa damages. Pectin films based on pectin at lower degrees of esterification have been further evaluated to study the influence of two different amounts of drug on the physicochemical properties of the formulation. A slight reduction in elasticity has been observed in films containing a higher drug dose; nevertheless, the formulation maintained satisfactory flexibility and resistance to elongation.

Conclusions: HPC and PC sublingual films, obtained by a simple casting method, could be proposed to realize personalized hospital pharmacy preparations on a small scale.     

Swelling Properties of Gelatin in Solvent Mixtures

Abstract

Gelatin is used as one component in ink receiving layers of some ink jet papers or foils. An important property for this application is the rapid absorption of solvents. We investigated the uptake of water and water diethylene glycol (DEG) mixtures of unsupported films of gelatin as a model system. The kinetics of the swelling properties of different types of gelatin were studied as a function ofpht and DEG content. The influence of additives upon the swelling of gelatin are discussed.     

Use of Proteins to Minimize the Physical Aging of EUDRAGIT® Sustained Release Films

ABSTRACT

The objective of this study was to investigate the influence of two proteins, albumin and type B gelatin, on the physical aging of EUDRAGIT® RS 30 D and RL 30 D coated theophylline pellets. The physicomechanical properties of sprayed films, thermal properties of cast films, influence of proteins on the zeta potential and particle size of the dispersion, and the release of proteins from cast films under simulated dissolution conditions were investigated. The release rate of theophylline decreased significantly over time from pellets coated with an acrylic dispersion containing 10% albumin when there was no acidification of the acrylic dispersion; however, when pellets were coated with an acidified EUDRAGIT®/albumin dispersion, the theophylline release rate was stable for dosage forms stored in the absence of humidity. The drug release rate was faster for pellets coated with acrylic dispersions containing 10% gelatin compared to the albumin–containing formulations. When sprayed films were stored at 40°C/75% RH, the water vapor permeability decreased significantly for both EUDRAGIT® films and those containing EUDRAGIT® and albumin; however, there was no significant change in this parameter when 10% gelatin was present. Albumin was released from the acrylic films when the pH of the dissolution media was below the isoelectric point of the protein while no quantitative release of gelatin was observed in pH 1.2 or 7.4 media. The effect of gelatin to prevent the decrease in drug release rate was due to stabilization in water vapor permeability of the film. Acidification of the polymeric dispersion resulted in electrostatic repulsive forces between albumin and the acrylic polymer, which stabilized the drug release rate when the dosage forms were stored in aluminum induction sealed containers at both 40°C/75% RH and 25°C/60% RH.     

Microstructure and properties of nc-TiC/a-C∶H films deposited by radio frequency reactive sputtering

Abstract

Amorphous carbon films containing titanium carbide (nc-TiC/a-C∶H) were deposited onto n-type silicon (100) by radio frequency reactive sputtering titanium target in an Ar–CH₄ mixed atmosphere. The composition and microstructure of the films were characterised by means of X-ray photoelectron spectroscopy, field emitted SEM, XRD and Raman spectra. The mechanical and tribological properties of the films were measured by a nanoindentation tester and a ball-on-disc UMT–2MT tribometer. By adjusting the CH₄ flowrate, Ti content in the films could be controlled, and a transition in structures of the films from loose polymer-like to glassy and dense nanostructure was observed. The density of coatings was improved by the introduction of TiC nanocrystalline particles. The mechanical and lubricious properties were different accordingly.     

Preparation and characterization of novel gelatin/cerium (III) fiber with antibacterial activity

Gelatin/Cerium (III) fibers with high tensile strength and good antibacterial activity were prepared by wet spinning method. The fiber structure and properties were investigated. The optical microscope (OPM) results showed that the fiber had a smooth surface and the fiber diameter was in the range of 60-90 µm. The mechanical properties tests showed that the tensile strength of gelatin/cerium (III) fibers increased greatly compared with the pure gelatin fibers. Furthermore, it was found that the gelatin/Ce (III) fibers have the antibacterial activity for Escherichia coli and Staphylococcus aureus.