Concentration Of Shellac Research Articles

Optimizing shellac nanoparticle fabrication: Influence of formulation and process parameters

This study aimed to fabricate shellac (SHL) nanoparticles by optimizing the formulation and electrospraying process. We investigated the influence of formulation factors, including solvent types and SHL concentration, and process parameters like feed rate and applied voltage, on physical appearance, particle size, size distribution, and aspect ratio. Optimized conditions were determined using a Box–Behnken design. It was found that particle formation was significantly affected by the type of solvent, SHL concentration, applied voltage, and feed rate. Under the optimized conditions, uniform spherical nanoparticles were achieved. Overall, this study presents a simple and effective approach to producing nanoparticles as potential nanocarriers for drugs and related compounds in future applications.

Preparation of microspheres with sustained ketoprofen release by electrospray for the treatment of aseptic inflammation.

The treatment of aseptic inflammation has always been a clinical challenge. At present, non-steroidal drug-loaded microspheres have been widely used in the treatment of aseptic inflammation due to their excellent injectable and sustained release capabilities. In this study, ketoprofen-loaded shellac microspheres (Keto-SLAC) were prepared by electrospray. Alterations of Keto-SLAC morphology was observed in response to changed shellac concentration in ethanol solution through electrospray. Further examination revealed that ketoprofen presented as amorphous solid dispersion in the shellac microspheres. Most importantly, it was also shown that ketoprofen can be slowly released from the shellac matrix for up to 3weeks. In vitro cell experiments verified that the microspheres had favorable cell compatibility. We therefore proposed that the prepared microspheres, being readily available in use in a variety of clinical settings through topical application, have promising therapeutic potential for the treatment of aseptic inflammation.

Designing electrospun shellac nanofibers with mupirocin using the Box-Behnken approach for topical wound care

This study attempted to develop shellac (SHL) nanofibers containing a topical antibiotic, mupirocin (MP), as an alternative wound healing material. The impacts of formulation and process parameters such as SHL concentration, MP content, and applied voltage on the morphology of fibers were examined based on a 33 Box-Behnken experimental design with triplicate center points. The results indicated that the amounts of polymeric SHL and encapsulated MP were considered factors affecting the morphology of fabricated fibers, including size and bead ratio. As the concentrations of SHL and MP increased, the large-sized fibers would be obtained. Meanwhile, the appearance of beads would be lessened with the enhanced amount of SHL. The excellent encapsulation of MP in SHL carrier was indicated by the high entrapment efficiency (88.12 ± 0.09% - 109.93 ± 3.23%) which might be possibly due to the ultrafine network and microporous structures of nanofibers and the good affinity of MP for entrapping between the polymeric SHL as referred to the results of the characterization study. According to the assay of antimicrobial activity, S. aureus, the leading cause of wound infection, was entirely killed since 5 min after exposure to the SHL nanofibers loaded with MP, and the regrowth of living S. aureus was not found throughout the next 6 h. Therefore, the SHL nanofibers containing MP seemed to be an effective wound dressing with high encapsulation efficiency and potential antimicrobial activity against S. aureus over a period of time.

Synthesis of curcumin‐loaded shellac nanoparticles via co‐precipitation in a rotating packed bed for food engineering

AbstractPractical application of versatile nanomaterials to food engineering is desirable. In this study, highly encapsulated curcumin‐loaded shellac (Cur@Lac) nanoparticles are efficiently prepared via a rotating packed bed (RPB). In this modified co‐precipitation process, the morphology of Cur@Lac nanoparticles is systematically investigated under experimental parameters involving the high‐gravity level, the volume of antisolvent and the concentration of shellac. By virtue of the highly structured polymeric ester matrices of shellac and adequate supersaturation brought from RPB on a microscale, the obtained Cur@Lac nanoparticles with uniform size exhibit high encapsulation efficiency of over 96%. After 2 months of storage at room temperature, the aqueous Cur@Lac nanodispersions exhibit long‐term stability with no agglomeration or sedimentation, and the final retention rate of curcumin was over 85%. Colored drinks of fruit syrup (pH = 4.0), fruit soda (pH = 6.0), and soda water (pH = 8.3) are prepared by using the Cur@Lac as the colorant, which possessed orange‐yellow color. The nanocomposites of alkali‐sensitive indicators based on cellulose paper and gelatin film demonstrated in the work show promising application value for sensing of alkaline solution and gas of perishable food.

Determination of changes in the mechanical and color properties of some wood species treated with shellac

The properties of wood, which is a natural and sustainable substance, change under biotic and abiotic factors. Different methods along with chemical/natural substances are used to extend the service life of wood and increase its performance under different conditions. Shellac is a natural product secreted by insects onto host trees. It is used extensively as a coating, especially in the food and pharmaceutical industries. Its natural properties and biocompatibility increase the areas where it is used. This study investigated the effects on the physical and mechanical properties of pine, beech, and fir species impregnated with shellac solutions at different concentrations (1%, 3%, and 5%) and sodium hydroxide (NaOH). The study found that 10% NaOH solution caused significant decreases in the bending strength values. The highest bending strength values were obtained for the Scots pine and fir woods at 5% shellac concentration and for the beech wood at 1% concentration. The highest modulus of elasticity (MOE) values were reached at 1% shellac concentration in all three tree species. Although the lightness (L*) of the wood samples decreased with shellac impregnation, the chromatic coordinate (a* and b*) values increased. According to the Fourier-transform infrared (FTIR) spectroscopy results, changes were determined in the chemical structures of the wood samples impregnated with NaOH, whereas the shellac did not cause a change in the chemical structure of the wood samples.

Preparation of a novel superabsorbent hydrogel based on polyacrylic acid/shellac using gamma irradiation for adsorption removal of malachite green dye

The objective of this study is to prepare a super absorbent hydrogel based on polyacrylic acid and an environmentally friendly material such as shellac to remove malachite green dye from aqueous solution using gamma radiation. The adsorption of malachite green (MG) dyes using polyacrylic acid (PAA)/shellac (SH) hydrogels was studied. These hydrogels were prepared by mixing aqueous solutions of PAA and SH at differing molecular ratios (10%, 20%, and 30% SH content in the final reaction mixture) and varying doses of gamma radiation (10–50 kGy). The water absorption by the PAA/SH hydrogels prepared at a 30-kGy radiation dose increased with an increase in the SH content. The removal of the MG dyes from an aqueous solution using PAA and PAA/SH hydrogels was investigated at different values for selected parameters, such as pH, contact time, SH concentration, and adsorbent dosage. The highest MG adsorption percentage (95.5%) was obtained for the PAA/SH hydrogel with the highest SH content (30%). As the adsorbent dosage increased, the dye adsorption capacity increased, accordingly. The combination of SH and gamma radiation caused the PAA to undergo structural changes verified by X-ray diffraction and Fourier transform infrared spectroscopy. Scanning electron microscopy was employed to investigate the morphology of the PAA/SH hydrogel and revealed that the SH belonging to the PAA matrixes exhibited a homogeneous dispersion. The thermal stability of the hydrogels was investigated by thermogravimetric analysis. The amount of dye adsorbed by the PAA/SH hydrogel was calculated by subtraction based on the ultraviolet–visible (UV–VIS) spectroscopy determination of the concentration of leftover dye in solution using a UV–VIS spectrophotometer.

Investigation into Effect of Natural Shellac on the Bonding Strength of Magnesium Substituted Hydroxyapatite Coatings Developed on Ti6Al4V Substrates

The bioactive and biocompatible properties of hydroxyapatite (HA) promote the osseointegration process. To enhance other bio-functions of HA such as improving the antibacterial property of the implant, increasing the rate of cell proliferation, or improving tissue generation capability, HA is substituted with many elements such as Zn, Cl, Ba, Fe, Cu, Ag, Sr, F, Na, etc. This study reports development of Magnesium substituted HA (Mg-HA) coatings on Ti6Al4V substrates using the dip coating technique. To improve the adhesion and stability of the coating, an intermediate layer of shellac was applied between the coating and Ti6Al4V substrate. The dip coating process parameters were optimized using the Taguchi technique and it was found that dipping time of 35 s and 13% w/w of shellac concentration provided the maximum bonding strength of 12.5 MPa. The biocompatibility, dissolution, and corrosion study of the developed coating using the optimal parameters obtained were carried out in this study. An improvement in cell growth and cell proliferation was observed in the extract medium prepared from coated substrates. Release of Ca, P and Mg ions from the surface of the coated substrate into the simulated body fluid (SBF) was found to be almost constant which shows the stability of the thin film coating formed. The Mg-HA coated substrate also exhibited better corrosion resistance than the uncoated substrate.

Tailoring the dispersibility of non-covalent functionalized multi-walled carbon nanotube (MWCNT) nanosuspension using shellac (SL) bio-resin: Structure-property relationship and cytotoxicity of shellac coated carbon nanotubes (SLCNTs)

This study first reports the use of natural thermoplastic bio-resin shellac (SL) to functionalize multi-walled carbon nanotubes (MWCNTs). The MWCNTs were coated with 5, 10, and 15 wt% SL solutions to fabricate SLCNT nanocomposites which are highly dispersible and stable in solution. Enhanced surface charge imparted long-term stabilization of SLCNT nanosuspension. Microscopic analysis revealed distinct dispersion of nanotubes and a thin layer of SL on the surface of nanotubes in the nanocomposite system. FTIR and Raman spectroscopy confirmed well interaction between SL and MWCNT in the nanocomposites. It was disclosed by the microstructure analysis that the SL concentration affects the lattice parameters of SLCNT nanocomposites. The thermal stability of SLCNT was impressive compared to MWCNT. According to the ROS (reactive oxygen species) generation profile and cell viability study, SLCNTs have reduced adverse effects on cells. Therefore, the results confirm that shellac can significantly improve the stability of MWCNT and reduce the cytotoxicity to facilitate their widespread applications.

Development of biocompatible coating on Ti6Al4V implant materials using chitosan extracted from shellfish waste

The present study focuses on extracting chitosan from crustacean shells. The as-prepared chitosan was used to develop a uniform thin layer coating on titanium alloy (Ti6Al4V) implant material. Shellac, a natural resin was used intermediately for providing better adhesion. Taguchi optimization technique was used to optimize the control parameter values. Dipping duration and concentration of shellac were considered as control parameters and adhesion strength & thickness of the coating were considered as response characteristics. The concentration of shellac significantly affected the adhesion strength, whereas the thickness increased with an increase in dipping duration. Cytotoxicity tests and corrosion studies were performed on the samples coated with optimal values. The chitosan-coated sample was found as non-toxic and also showed better corrosion resistance.

REDUCTION OF OIL UPTAKE FROM POTATO FENCH FRIES BY PLASTICISER SHELLAC AND ULTRASOUND TECHNOLOGY

Edible lac resin, shellac in different concentrations was used as a coating agent to reduce the oil uptake in deep-fried potato fries. The coating formulation was carried out by Shellac and D-Sorbitol. Shellac used in the concentrations 0%, 1%, 2%, 3%, 4% and 5% in combination with 0.25% D-sorbitol. Further coated samples were treated with ultrasonication for 5 minute and 10 minutes at 50 Hz. Potato fries coated with shellac and ultrasonicated were deep fried and analyzed for oil uptake, moisture content, color and sensory analysis. The oil content and moisture content of deep fried potato fries were determined using standard AOAC method, the colour analysis was carried out by software-based application and sensory analysis was carried out by a 9 point hedonic scale by 30 untrained panelists. With the increase in the concentration of shellac, the oil uptake by potato fries significantly reduced showing the highest reduction of 54.24% in 5% shellac coated potato fries. Potato fries coated with 5% shellac and ultrasonicated for 5 minutes showed 55.07% reduction whereas at 10 minutes, it showes reduction of 57.87%.

Modulation of release mechanisms of methylene blue (MB) monomers and dimers from silica-MB@shellac synthesized by antisolvent crystallization

Release behaviors of drugs from drug deliveries are crucial for the enhancement of therapy efficiency, reduction of toxicity and patient compliance. Herein, antisolvent crystallization is employed to coat methlyene blue (MB)-loaded silica by shellac precipitation (silica-MB@shellac), which is simultaneously induced by outward diffusion of H+ ions from particular silica-MB. The encapsulation of shellac shell on silica-MB modulates the aggregation state of MB, which endows silica-MB@shellac a decreased MB's thermal stability, enhanced photoluminescence intensity, improved stability against in vitro reduction by ascorbic acid and retained photodynamic therapy activity. From the absorbance of MB supernatant obtained during incubation, the concentrations of MB monomers and dimers are determined via a non-linear regression analysis to investigate the influence of shellac coating on MB's release mechanisms from silica-MB@shellac. According to the simulated models, small diffusion constants of MB are caused by limited diffusion through shellac shells with high compaction degrees. These are observed for samples synthesized under high supersaturation degree during antisolvent crystallization. High degree of supersaturation is achieved through increasing shellac concentration, additive amount and dropping rate of antisolvent, as well as decreasing pH values of aqueous buffers as antisolvent. Furthermore, a combined mechanism of Fickian diffusion and Case-IΙ relaxation is proposed to describe the release behaviors of MB monomer and dimers from silica-MB@shellac. Therefore, this work may shed light on the encapsulation method of polymer on drug-loaded powders and the control of aggregation states of photosensitizers to promote the photoluminescence intensity, photodynamic therapy efficiency and controlled release behaviors.

Modelling the Effect of Process Parameters on the Wet Extrusion and Spheronisation of High-Loaded Nicotinamide Pellets Using a Quality by Design Approach.

The aim of the present study was to develop an alternative process to spray granulation in order to prepare high loaded spherical nicotinamide (NAM) pellets by wet extrusion and spheronisation. Therefore, a quality by design approach was implemented to model the effect of the process parameters of the extrusion-spheronisation process on the roundness, roughness and useable yield of the obtained pellets. The obtained results were compared to spray granulated NAM particles regarding their characteristics and their release profile in vitro after the application of an ileocolon targeted shellac coating. The wet extrusion-spheronisation process was able to form highly loaded NAM pellets (80%) with a spherical shape and a high useable yield of about 90%. However, the water content range was rather narrow between 24.7% and 21.3%. The design of experiments (DoE), showed that the spheronisation conditions speed, time and load had a greater impact on the quality attributes of the pellets than the extrusion conditions screw design, screw speed and solid feed rate (hopper speed). The best results were obtained using a low load (15 g) combined with a high rotation speed (900 m/min) and a low time (3–3.5 min). In comparison to spray granulated NAM pellets, the extruded NAM pellets resulted in a higher roughness and a higher useable yield (63% vs. 92%). Finally, the coating and dissolution test showed that the extruded and spheronised pellets are also suitable for a protective coating with an ileocolonic release profile. Due to its lower specific surface area, the required shellac concentration could be reduced while maintaining the release profile.

Preparation and properties of paper coating based bilayer of starch and shellac composites

The preparation and properties of paper coating based bilayer of starch and shellac composites has been investigated in the present report. The bilayer coating were prepared by coating the surface of the paper using starch as first layer then shellac was coated on the surface of the starch layer. Composition of the bilayer composites of starch/shellac was 20:80, 30:70, 40:60, 50:50; 60:40; 70:30; 80:20; % w/w. The Payne Cup Analysis showed that the water vapour barrier properties of starch/shellac increased with the increased of shellac concentration, and very significant improvement was achieved when shellac concentration was above 50 wt%. The grease resistance of the sample was better than that of conventional paper coating. The Diffuse Reflectance UV showed that the transparency of the samples did not change by the presence of the bilayer composites. XRD indicatedd that the stability of shellac was improved by the presence of starch.

Enhancement of Moisture Protective Properties and Stability of Pectin through Formation of a Composite Film: Effects of Shellac and Plasticizer.

The composite film with 50% shellac could improve moisture protective properties of pectin film. Adding a plasticizer could build up the higher mechanical characteristics of composite film. Stability of pectin could be modified by fabrication of composite films with proper content of shellac and plasticizer.

Design of Experiment Approach for Fabrication Process of Electrospun Shellac Nanofibers Using Factorial Designs

Electrospun shellac nanofibers might be potentially used for wound dressing application due to its natural origin and excellent protective properties. In this study, a full factorial design with three replicated center points was performed in order to investigate the main and interaction effects of shellac content (35-40% w/w), applied voltage (9-27 kV) and flow rate (0.4-1.2 mL/hr) on the morphology of shellac nanofibers. A total of 11 experiments were conducted. The response variables were the diameter of nanofibers, the distribution of diameter and the amount of beads. The results showed that the concentration of shellac was the most significant impact on shellac nanofiber diameter, while applied voltage, interaction between shellac content and voltage, and feed rate were minor factors, respectively. Shellac content and applied voltage had negative relationships with bead amount. When reducing the concentration of shellac and voltage, the amount of beads was increased. However, the influence of these parameters on diameter distribution seemed to be not significant. Based on response surface plot, nanofibers with thinner diameter (~493 nm) and less number of beads (~0.47) could be obtained at the optimum conditions; the shellac content of 38.5% w/w, the voltage of 21 kV and the feed rate of 0.4 mL/hr.

Development of biocomposite films incorporated with different amounts of shellac, emulsifier, and surfactant

This study examined the effects of different ratios of shellac (20–60%), stearic acid (SA) (0–2%), and Tween-20 (0.1–0.5 ml) on the water vapor permeability (WVP) and mechanical properties of the pea starch-guar gum (PSGG) films which were evaluated by using response surface methodology (RSM). The incorporation of shellac into the PSGG film structure led to a slightly increased of film thickness. However the addition of higher concentrations of shellac did not improve the moisture barrier of PSGG film owing to the poor distribution of shellac in the film structure. Film formulated with 40% shellac, 1% SA, and 0.3% Tween-20 exhibited optimal functional properties. Moreover, the influence of the incorporation of different emulsifiers into the optimized film matrix was investigated by studying the physical, mechanical, and optical properties of the films. Films containing oleic acid (OA) showed not only lower thickness, WVP, moisture content, and water solubility, but also higher percentage of elongation (E), tensile strength (TS), and transparency compared with other fatty acids tested. Biocomposite pea starch-guar gum-shellac (PSGG-Sh) films containing OA can be considered to be sufficient for most of food packaging applications.

Physico-chemical properties of alginate/shellac aqueous-core capsules: Influence of membrane architecture on riboflavin release

To enhance physico-chemical properties of alginate liquid-core capsules, shellac was incorporated into the membrane (composite capsules) or as an additional external layer (coated capsules). The influence of pH, coating time, shellac concentration and preparation mechanism (acid or calcium precipitation) were investigated. Results showed that shellac significantly influenced the capsules properties. The feasibility of shellac incorporation was closely related to the preparation conditions as confirmed by Infrared spectroscopy. Optical, fluorescence and scanning electron microscopy, highlighted different capsules and membranes architectures. In contrast to simple and composite capsules, coated capsules showed a pH-dependent release of the entrapped vitamin especially after shellac crosslinking with calcium. Heating of coated capsules above the glass transition temperature investigated by Differential Scanning Calorimetry, led to irreversible structural change due to thermoplastic behavior of shellac and enhanced riboflavin retention under acidic conditions. This global approach is useful to control release mechanism of low molecular weight molecules from macro and micro-capsules.

Ferulic Acid-Loaded Shellac Microparticles Prepared Using Electrohydrodynamic Atomization

An Electrohydrodynamic atomization (EHDA) process was exploited to prepare ferulic acid (FA)-loaded shellac microparticles. SEM observations showed that all the particles were round and solid with their sizes gradually increased from 0.68 ± 0.21 to 2.75 ± 0.64 μm as the concentrations of shellac and FA in ethanol raised from 20% to 50% (w/v). Wide-angle X-ray diffraction analyses demonstrated that FA had been totally converted into an amorphous state in the shellac matrix microparticles. Attenuated total reflectance Fourier transform infrared analysis disclosed that the hydrogen bonding presented between FA and shellac molecules. In vitro dissolution tests verified that all the microparticles were able to provide a fine sustained drug release profile. The release time periods had a close relationship with the diameters of microparticles. All the microparticles released the loaded FA via a typical Fickian diffusion mechanism. The present study provides an easy way to develop novel drug delivery microparticles for providing sustained drug release profiles.

Shellac as a natural material to structure a liquid oil-based thermo reversible soft matter system

We demonstrate the novel use of shellac as a natural material to structure liquid oil into an oleogel. Thermo reversible oleogels with different texture, gel strength and temperature behaviour could be obtained by altering the concentration of shellac. Further, a possible application of shellac oleogel in the preparation of w/o spreadable emulsions is described.

Formation and characterization of shellac-hydroxypropyl methylcellulose composite films

Shellac-hydroxypropyl methylcellulose composite films (Sh-HPMC-CFs) were produced and the effects of emulsifier and shellac concentration on the Sh-HPMC-CFs were investigated. Two emulsifiers, stearic acid (SA) and lauric acid (LA), with three ratios of shellac to emulsifier (100:1, 20:1, and 10:1) were tested to select the best ratio of shellac to emulsifier before testing the effect of shellac concentration. When compared to pure HPMC film, the WVP was decreased by 6 and 11% in the Sh-HPMC-CFs containing shellac to LA (ShLA) ratios of 100:1 and 20:1, respectively. However, all the ShSA-HPMC-CFs had higher WVP than the pure HPMC film. In relation to mechanical properties, the ShLA(20:1)-HPMC-CF had the lowest reduction in TS when compared to a pure HPMC film. Therefore, ShLA(20:1) was selected for further characterization. Surface morphology, cross sectional image, thermal stability, WVP, and mechanical properties of the Sh-HPMC-CFs were also measured at varying shellac concentrations (0.1, 0.5, 1.0, and 1.5%). The 0.1 and 0.5% Sh-HPMC-CFs had good distribution of shellac in the film structure while the 1.0 and 1.5% Sh-HPMC-CFs exhibited some agglomeration of shellac. The 0.1 and 0.5% Sh-HPMC-CFs had better moisture barrier than the pure HPMC film. All Sh-HPMC-CFs had better thermal stability than the pure HPMC film and its thermal stability increased as shellac concentration increased.