Optimizing interactions between soluble silk fibroin and capryl glucoside for design of a natural and high-performance co-surfactant system.

OBJECTIVES: Because of the strong consumer driver towards more natural or higher sustainability cosmetic products, silk fibroin was evaluated to help develop a formulation with natural and effective ingredients for personal care. In order to exploit the physical properties of silk fibroin, it was evaluated to maximize the surfactant properties of other commercial ingredients to lower surface tension and build up viscosity. A synergistic effect was seen between silk fibroin and capryl glucoside, a sugar surfactant which exhibited a natural and effective co-surfactant system. This system demonstrated better surface tension properties than sodium laureth sulphate (SLES), cocamidopropyl betaine (CAPB), rhamnolipids and sophorolipids, which led to greater foamability and cleansing properties. This system proved to also be compatible with polysaccharide viscosity modifiers to enhance the viscosity of the system. The present study comprises a systematic exploration of natural formulation development of silk proteins and other natural ingredients, which result in high performance such as enhanced foam quality, foam stability and enhanced sebum removal. All of these properties are desirable and may utilized when formulating cleaners and shampoos. METHODS: A force tensiometer, Attension Sigma 701, was used to measure the surface tension of the silk protein and its various combinations with biosurfactants and biopolymers. To measure bulk rheology, a traditional mechanical rheometer TA DHR-3 was utilized. Foaming tests and sebum removal assays were also carried out to evaluate the performance of the samples. RESULTS: Silk fibroin was evaluated to maximize the surfactant properties of other commercial systems to develop a formulation containing natural and effective ingredients for personal care. The surface activity of silk proteins was seen to be synergistically enhanced in the presence of sugar surfactants such as capryl glucoside, resulting in a surface tension at the air-water interface which is lower than either that of pure silk fibroin or pure capryl glucoside. This surface tension value is additionally lower than that obtained from currently utilized synthetic surfactants like sodium laureth sulphate (SLES) and cocamidopropyl betaine (CAPB). This reduction in surface tension demonstrated greater foamability and cleansing properties than that of the commercial systems. The very low surface tension values obtained through combinations of silk proteins and glucoside resulted in a natural and effective co-surfactant system by forming high-quality stable foams and enhancing sebum removal. The rheological performance of the silk proteins was impacted through microstructure modifications as a result of interactions with biopolymers like carrageenan. This shows that this system is compatible with polysaccharide viscosity modifiers. It was observed that both the flow curve and the absolute viscosity values were significantly impacted in the presence of carrageenan, with higher viscosity generation and significant non-Newtonian/shear thinning behaviour evolution. These results indicate that the silk fibroin can be utilized to build a high-performance natural product and significantly enhance the performance of other natural/sustainable cosmetic formulations through building synergistic interactions with other natural ingredients such as sugar surfactants and biopolymers. These properties exhibited by this system are all desirable for cleansers and shampoos within the cosmetic industry. CONCLUSION: Silk fibroin in combination with capryl glucoside outperforms other commercial surfactants that are commonly used in the industry because of its surface-active behaviour and synergy. This system is then enhanced further with polysaccharide rheological modifiers, carrageen and xanthan gum to help build up viscosity. The complex mixture of silk fibroin, sugar surfactant and biopolymer results in a formulation that is all natural, while still having high performance by achieving great foamability and enhanced sebum removal. The mixture can further be used to formulate a fully natural product such as a cleanser or shampoo while still having the same or greater effectiveness as synthetic surfactants and ingredients typically used in cosmetic formulations.

OBJECTIFS: En raison de la forte incitation des consommateurs vers des produits cosmétiques plus naturels ou plus durables, la fibroïne de soie a été évaluée pour aider à développer une formulation avec des ingrédients naturels et efficaces pour les soins personnels. Afin d'exploiter les propriétés physiques de la fibroïne de soie, il a été évalué pour maximiser les propriétés tensioactives d'autres ingrédients commerciaux pour abaisser la tension superficielle et augmenter la viscosité. Un effet synergique a été observé entre la fibroïne de soie et le capryl glucoside, un tensioactif de sucre qui présentait un système de co-tensioactif naturel et efficace. Ce système a démontré de meilleures propriétés de tension superficielle que le laureth sulfate de sodium (SLES), la cocamidopropyl bétaïne (CAPB), les rhamnolipides et les sophorolipides, ce qui a conduit à une plus grande moussabilité et des propriétés de nettoyage. Ce système s'est avéré également compatible avec les modificateurs de viscosité polysaccharidiques pour améliorer la viscosité du système. La présente étude comprend une exploration systématique du développement de formulation naturelle de protéines de soie et d'autres ingrédients naturels, qui se traduisent par des performances élevées telles qu'une qualité de mousse améliorée, une stabilité de la mousse et une élimination améliorée du sébum. Toutes ces propriétés sont souhaitables et peuvent être utilisées lors de la formulation de nettoyants et de shampooings. MÉTHODES: Un tensiomètre de force, Attension Sigma 701, a été utilisé pour mesurer la tension superficielle de la protéine de soie et ses diverses combinaisons avec des biosurfactants et des biopolymères. Pour mesurer la rhéologie de masse, un rhéomètre mécanique traditionnel TA DHR-3 a été utilisé. Tests de moussage et dosages d'élimination du sébum ont également été réalisés pour évaluer les performances des échantillons. RÉSULTATS: La fibroïne de soie a été évaluée pour maximiser les propriétés tensioactives d'autres systèmes commerciaux afin de développer une formulation contenant des ingrédients naturels et efficaces pour les soins personnels. L'activité de surface des protéines de soie s'est avérée être renforcée de manière synergique en présence d'agents tensioactifs de sucre tels que le capryl glucoside, entraînant une tension de surface à l'interface air-eau qui est inférieure à celle de la fibroïne de soie pure ou du capryl glucoside pur. Cette valeur de tension superficielle est en outre inférieure à celle obtenue à partir d'agents tensioactifs synthétiques actuellement utilisés comme le laureth sulfate de sodium (SLES) et la cocamidopropyl bétaïne (CAPB). Cette réduction de la tension superficielle a démontré une moussabilité et des propriétés de nettoyage supérieures à celles des systèmes commerciaux. Les très faibles valeurs de tension superficielle obtenues grâce à des combinaisons de protéines de soie et de glucoside ont abouti à un système de co-tensioactif naturel et efficace en formant des mousses stables de haute qualité et en améliorant l'élimination du sébum. Les performances rhéologiques des protéines de soie ont été affectées par des modifications de microstructure à la suite d'interactions avec des biopolymères comme le carraghénane. Cela montre que ce système est compatible avec les modificateurs de viscosité polysaccharidiques. Il a été observé que la courbe d'écoulement et les valeurs de viscosité absolue étaient significativement affectées en présence de carraghénane, avec une génération de viscosité plus élevée et une évolution significative du comportement d'amincissement non newtonien / cisaillement. Ces résultats indiquent que la fibroïne de soie peut être utilisée pour construire un produit naturel haute performance et améliorer considérablement les performances d'autres formulations cosmétiques naturelles / durables en créant des interactions synergiques avec d'autres ingrédients naturels tels que les tensioactifs de sucre et les biopolymères. Ces propriétés présentées par ce système sont toutes souhaitables pour les nettoyants et les shampooings dans l'industrie cosmétique. CONCLUSION: La fibroïne de soie en combinaison avec le capryl glucoside surpasse les autres tensioactifs du commerce couramment utilisés dans l'industrie en raison de son comportement tensioactif et de sa synergie. Ce système est ensuite amélioré avec des modificateurs rhéologiques polysaccharidiques, de la carraghénine et de la gomme xanthane pour aider à augmenter la viscosité. Le mélange complexe de fibroïne de soie, de tensioactif de sucre et de biopolymère donne une formulation entièrement naturelle, tout en conservant des performances élevées en obtenant une grande capacité de moussage et une élimination améliorée du sébum. Le mélange peut en outre être utilisé pour formuler un produit entièrement naturel tel qu'un nettoyant ou un shampooing tout en ayant toujours la même efficacité ou une plus grande efficacité que les tensioactifs synthétiques et les ingrédients généralement utilisés dans les formulations cosmétiques.

Local, Controlled Delivery of Local Anesthetics In Vivo from Polymer - Xerogel Composites.

PURPOSE: Polymer-xerogel composite materials have been introduced to better optimize local anesthetics release kinetics for the pain management. In a previous study, it was shown that by adjusting various compositional and nano-structural properties of both inorganic xerogels and polymers, zero-order release kinetics over 7 days can be achieved in vitro. In this study, in vitro release properties are confirmed in vivo using a model that tests for actual functionality of the released local anesthetics. METHODS: Composite materials made with tyrosine-polyethylene glycol(PEG)-derived poly(ether carbonate) copolymers and silica-based sol-gel (xerogel) were synthesized. The in vivo release from the composite controlled release materials was demonstrated by local anesthetics delivery in a rat incisional pain model. RESULTS: The tactile allodynia resulting from incision was significantly attenuated in rats receiving drug-containing composites compared with the control and sham groups for the duration during which natural healing had not yet taken place. The concentration of drug (bupivacaine) in blood is dose dependent and maintained stable up to 120 h post-surgery, the longest time point measured. CONCLUSIONS: These in vivo studies show that polymer-xerogel composite materials with controlled release properties represent a promising class of controlled release materials for pain management.

Enzymatic surface erosion of high tensile strength polycarbonates based on natural phenols.

Surface erosion has been recognized as a valuable design tool for resorbable biomaterials within the context of drug delivery devices, surface coatings, and when precise control of strength retention is critical. Here we report on high tensile strength, aromatic-aliphatic polycarbonates based on natural phenols, tyrosol (Ty) and homovanillyl alcohol (Hva), that exhibit enzymatic surface erosion by lipase. The Young's moduli of the polymers for dry and fully hydrated samples are 1.0 to 1.2 GPa and 0.8 to 1.2 GPa, respectively. Typical characteristics of enzymatic surface erosion were confirmed for poly(tyrosol carbonate) films with concomitant mass-loss and thickness-loss at linear rates of 0.14 ± 0.01 mg cm(-2) d(-1) and 3.0 ± 0.8 µm d(-1), respectively. The molecular weight and the mechanical properties of the residual films remained constant. Changing the ratio of Ty and Hva provided control over the glass transition temperature (T(g)) and the enzymatic surface erosion: increasing the Hva content in the polymers resulted in higher T(g) and lower enzymatic erosion rate. Polymers with more than 50 mol % Hva were stable at 37 °C in enzyme solution. Analysis on thin films using quartz crystal microbalance with dissipation (QCM-D) demonstrated that the onset temperature of the enzymatic erosion was approximately 20 °C lower than the wet T(g) for all tested polymers. This new finding demonstrates that relatively high tensile strength polycarbonates can undergo enzymatic surface erosion. Moreover, it also sheds light on the connection between T(g) and enzymatic degradation and explains why few of the high strength polymers follow an enzyme-meditated degradation pathway.

Polymer-xerogel composites for controlled release wound dressings.

Many polymers and composites have been used to prepare active wound dressings. These materials have typically exhibited potentially toxic burst release of the drugs within the first few hours followed by a much slower, potentially ineffective drug release rate thereafter. Many of these materials also degraded to produce inflammatory and cytotoxic products. To overcome these limitations, composite active wound dressings were prepared here from two fully biodegradable and tissue compatible components, silicon oxide sol-gel (xerogel) microparticles that were embedded in tyrosine-poly(ethylene glycol)-derived poly(ether carbonate) copolymer matrices. Sustained, controlled release of drugs from these composites was demonstrated in vitro using bupivacaine and mepivacaine, two water-soluble local anesthetics commonly used in clinical applications. By systematically varying independent compositional parameters of the composites, including the hydrophilic:hydrophobic balance of the tyrosine-derived monomers and poly(ethylene glycol) in the copolymers and the porosity, weight ratio and drug content of the xerogels, drug release kinetics approaching zero-order were obtained. Composites with xerogel mass fractions up to 75% and drug payloads as high as 13% by weight in the final material were fabricated without compromising the physical integrity or the controlled release kinetics. The copolymer-xerogel composites thus provided a unique solution for the sustained delivery of therapeutic agents from tissue compatible wound dressings.