Synthesis of Water-Soluble Chitosan From Squid Pens Waste for Capsule Shell Materials

Water-Soluble Chitosan(WSC)has been sucessfuly synthesized from squid pens waste.The synthesis of chitosan from chitin was carried out by optimization of deacetylation temperature and time.Chitin was obtained from squid pens waste by demineralization and deproteinization process.HCl 7%was used for demineralization and NaOH 10%at 60℃ was applied for deproteinization process.Deacetylation reaction was carried out at varied temperatures i.e.,60℃,70℃,80℃,90℃ and 100℃ in NaOH 50%solution for 10 hours.Deacetylation reaction time were varied for 2 hours,4 hours,6 hours,8 hours,and 10 hours.The crude chitosan obtained then reacted with H2O230%to depolymerize.The synthesis product obtained then characterized by FTIR.The result of squid chitin yield was 33.9%.The optimum temperature and time of chitosan deacetylation process were 90℃ for 8 hours as indicated by the value of deacetylation degree(DD)that equal to 83.94%at optimum temperature and 82.22%at optimum reaction time.The percentage of WSC yield at optimum temperature(90℃)and optimum time(8 hours)were 27.59%and 23.16%,respectively.WSC solubility test was done in water and HCl 0,1N.The solubility of 2.8325 mg/mL and 0.8125 mg/mL were obtained in acid medium and water medium,respectively.

Preparation and characterization of complexes of RE^(3+) with furfural modified water-soluble chitosan

Degraded chitosan, with highly water-solubility, was obtained by the oxidation of chitosan with H2O2, and then reacted with furrural. The final product coordinated with the rare earth ions （RE^3＋ = Sm^3＋, Eu^3＋）, which led to the formation of the complexes. The prepared complexes were characterized with Infrared Spectroscopy （IR）, Ultra Violet （UV）, fluorescence, X-Ray Diffraction （XRD）, and Thermogravimetric-Differential Scanning Calorimetry （TG-DSC） measurements.

Elastosonographic Changes in Patients with Peyronie's Disease, before and after Treatment with a Compound Based on <i>Ecklonia bicyclis</i>, <i>Tribulus terrestris</i>, and Water-Soluble Chitosan

Several diagnostic techniques have been proposed during the time for the diagnostic evaluation of Induratio Penis Plastica (IPP), due to poor sensitivity and specificity of standard B-Mode Ultrasonography. Shear-Wave elastosonography (SWE) is a relative new ultrasound technique, already used for several organs, which allows evaluating the rigidity of the tissues. Furthermore, we used a compound consisting of Ecklonia bicyclis, Tribulus terrestris, and Biovis (water-soluble Chitosan) with antifibrotic and antioxidant properties and analyzed the elastosonographic variations following the assumption of the compound. From March 2016 to April 2017, 40 patients were recruited with a mean age of 62. All patients underwent elastosonographic measurements at the start of treatment. Subsequently each patient took 1 tablet of the compound of Ecklonia bicyclis, Tribulus terrestris, and Biovis (water-soluble Chitosan) for 6 months. All patients underwent elastosonographic investigation at the end of treatment. The elastosonographic measurement prior treatment, showed that the average of the three measurements (proximal, medial and distal), was 37.05 KPa ± 7.76 SD and 38.8 KPa ± 10.11 SD for the left and right cavernous body, respectively. The examination at the end of the six months of treatment, with the compound showed that the average values of fibrosity were 31.07 KPa ± 7.5 SD and 30.86 KPa ± 11.4 SD for the left and right cavernous body respectively, demonstrating a decrease in fibrosity that was statistically significant (P < 0.01). Our data demonstrate that taking the compound for six months reduces the stiffness of the corpora cavernosa.

The Fabrication of Water-Soluble Chitosan Capsule Shell Modified by Alginate and Gembili Starch(Dioscorea esculenta L)

Capsule shells have been successfully fabricated from water-soluble chitosan(WSC)with the addition of alginate and Gembili starch.WSC was synthesized from crab shell chitosan by depolymerization reaction.The capsule shells were made with the composition of WSC:Alginate,2:1,3:1 and 4:1(w/w)with and without the addition of Gembili starch.Gembili starch was added with a ratio of Alginate:Starch,1:1(w/w).The capsule shell properties were evaluated according to Indonesian Pharmacopoeia standard.The solubility test showed that the capsule shells were comply with the standard.The highest degrees of swelling in water and HCl 0.1 N solution were 491.93%and 410.51%,respectively.The highest degradation percentages in water and HCl 0.1 N solution were 57.80%and 21.44%,respectively.The observation of physical appearance indicated that the capsule shell with WSC:Alginate:Starch in ratio of 3:1:1 has appearance close to commercial capsule shell.

Activation of endogenous neurogenesis and angiogenesis by basic fibroblast growth factor-chitosan gel in an adult rat model of ischemic stroke

Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactive materials can repair the damage caused by ischemic stroke by activating endogenous neurogenesis and angiogenesis is still unknown.In this study,we applied chitosan gel loaded with basic fibroblast growth factor to the stroke cavity 7 days after ischemic stroke in rats.The gel slowly released basic fibroblast growth factor,which improved the local microenvironment,activated endogenous neural stem/progenitor cells,and recruited these cells to migrate toward the penumbra and stroke cavity and subsequently differentiate into neurons,while enhancing angiogenesis in the penumbra and stroke cavity and ultimately leading to partial functional recovery.This study revealed the mechanism by which bioactive materials repair ischemic strokes,thus providing a new strategy for the clinical application of bioactive materials in the treatment of ischemic stroke.

Effect of formulation variables on in vitro release of a water-soluble drug from chitosanesodium alginate matrix tablets

The objective of this study is to investigate the feasibility of using chitosanesodium alginate(CSeSA)based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables.Using trimetazidine hydrochloride(TH)as a water-soluble model drug,influence of dissolution medium,the amount of CSeSA,the CS:SA ratio,the type of SA,the type and amount of diluents,on in vitro drug release from CSeSA based matrix tablets were studied.Drug release kinetics and release mechanisms were elucidated.In vitro release experiments were conducted in simulated gastric fluid(SGF)followed by simulated intestinal fluid(SIF).Drug release rate decreased with the increase of CSeSA amount.CS:SA ratio had only slight effect on drug release and no influence of SA type on drug release was found.On the other hand,a large amount of water-soluble diluents could modify drug release profiles.It was found that drug release kinetics showed the best fit to Higuchi equation with Fickian diffusion as the main release mechanism.In conclusion,this study demonstrated that it is possible to design extended-release tablets of watersoluble drugs using CSeSA as the matrix by optimizing formulation components,and provide better understanding about drug release from CSeSA matrix tablets.

Constructing a biofunctionalized 3D-printed gelatin/sodium alginate/chitosan tri-polymer complex scaffold with improvised biological andmechanical properties for bone-tissue engineering

Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue regeneration.We experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and differentiation.The resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)printing.Morphological studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural stability.The scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue engineering.The tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of gelatin.The enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue regeneration.In vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold surface.In addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its potential for use in bone-tissue engineering.

Chitosan/Sodium Alginate Multilayer pH-Sensitive Films Based on Layer-by-Layer Self-Assembly for Intelligent Packaging

The abuse of plastic food packaging has brought about severe white pollution issues around the world.Developing green and sustainable biomass packaging is an effective way to solve this problem.Hence,a chitosan/sodium alginate-based multilayer film is fabricated via a layer-by-layer(LBL)self-assembly method.With the help of superior interaction between the layers,the multilayer film possesses excellent mechanical properties(with a tensile strength of 50 MPa).Besides,the film displays outstanding water retention property(blocking moisture of 97.56%)and ultraviolet blocking property.Anthocyanin is introduced into the film to detect the food quality since it is one natural plant polyphenol that is sensitive to the pH changes ranging from 1 to 13 in food when spoilage occurs.It is noted that the film is also bacteriostatic which is desired for food packaging.This study describes a simple technique for the development of advanced multifunctional and fully biodegradable food packaging film and it is a sustainable alternative to plastic packaging.

Chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor for neurotrophic keratopathy

Neurotrophic keratopathy is a persistent defect of the corneal epithelium,with or without stromal ulceration,due to corneal nerve deficiency caused by a variety of etiologies.The treatment options for neurotrophic keratopathy are limited.In this study,an ophthalmic solution was constructed from a chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor(CTH-mNGF).Its effectiveness was evaluated in corneal denervation(CD)mice and patients with neurotrophic keratopathy.In the preclinical setting,CTH-mNGF was assessed in a murine corneal denervation model.CTH-mNGF was transparent,thermosensitive,and ensured sustained release of mNGF for over 20 hours on the ocular surface,maintaining the local mNGF concentration around 1300 pg/mL in vivo.Corneal denervation mice treated with CTH-mNGF for 10 days showed a significant increase in corneal nerve area and total corneal nerve length compared with non-treated and CTH treated mice.A subsequent clinical trial of CTH-mNGF was conducted in patients with stage 2 or 3 neurotrophic keratopathy.Patients received topical CTH-mNGF twice daily for 8 weeks.Fluorescein sodium images,Schirmer’s test,intraocular pressure,Cochet-Bonnet corneal perception test,and best corrected visual acuity were evaluated.In total,six patients(total of seven eyes)diagnosed with neurotrophic keratopathy were enrolled.After 8 weeks of CTH-mNGF treatment,all participants showed a decreased area of corneal epithelial defect,as stained by fluorescence.Overall,six out of seven eyes had fluorescence staining scores<5.Moreover,best corrected visual acuity,intraocular pressure,Schirmer’s test and Cochet-Bonnet corneal perception test results showed no significant improvement.An increase in corneal nerve density was observed by in vivo confocal microscopy after 8 weeks of CTH-mNGF treatment in three out of seven eyes.This study demonstrates that CTH-mNGF is transparent,thermosensitive,and has sustained-release properties.Its effectiveness in healing corneal epithelial defects in all eyes with neurotrophic keratopathy suggests CTH-mNGF has promising application prospects in the treatment of neurotrophic keratopathy,being convenient and cost effective.

Water-soluble chitosan nanoparticles as a novel carrier system for protein delivery

High MW chitosan (CS) solutions have already been proposed as vehicles for protein delivery. The aim of the present work is to investigate the potential utility of water-soluble chitosan (WSC) as vehicles to load and deliver proteins. WSC nanoparticles (WSC NP) with various formations were prepared based on ionic gelation of WSC with pentasodium tripolyphosphate (TPP) anions. Bovine serum albumin (BSA) was used as a model protein drug incorporated into the WSC nanoparticles. Blank and BSA-loaded WSC nanoparticles were examined and determined to have a spherical shape with diameters between 35―190 nm, and zeta potential between 35―42 mV. FTIR confirmed that the tripolyphosphoric groups of TPP linked to the ammonium groups of WSC in the nanoparticles. Some factors affecting delivery properties of BSA have been investigated. Altering the concentration of BSA from 0.05 to 1 mg/mL enhanced the loading capacity of BSA but decreased loading efficiency simultaneously. Also, with the introduction of poly ethylene glycol (PEG), BSA release accelerated. Nanoparticle preparation from WSC with various deacetylation degrees (DDs) from 72.6% to 90% and MWs ranging from 3.5 to 15.8 kDa promoted loading efficiency and decreased the release rate. These results indicate that WSC nanoparticles are promising carriers for protein delivery.

Adding chitosan nanoparticles of green tea extract in diluent and thawing temperatures ameliorate the post-thawed quality of Boer buck semen

Objective:To improve the quality of post-thawing Boer buck semen for artificial insemination by adding green tea extract chitosan nanoparticles to skimmed egg yolk diluent,and the proper thawing temperature.Methods:The ejaculate of Boer buck was added to skimmed egg yolk diluent without(the control group)and with adding 1μg of chitosan nanoparticles of green tea extract per mL of diluent(the treatment group).Then,the diluted semen was filled in French mini straws containing 60×106 live sperm per straw,frozen in a standard protocol,and stored as frozen semen at−196℃for a week.Six replicates from each group were diluted for 30 s at 37℃or 39℃sterile water to evaluate the semen quality.Results:Post-thawing(at 37℃or 39℃)of live sperm,progressive motility,and plasma membrane integrity were lower compared to those of the pre-freezing stage(P<0.05).Thawing at 37℃resulted in no significant difference in live sperm,progressive motility,and plasma membrane between the control group and the treatment group(P>0.05).The live sperm,progressive motility,and plasma membrane of the treatment group in the pre-freezing stage,and post-thawed at 39℃were higher compared to those of the control group(P<0.05).There was no significant difference in malondialdehyde(MDA)concentration,DNA fragmentation,and catalase concentration of thawing at 37℃compared to those of 39℃in the same group.The MDA concentration and DNA fragmentation in thawing at 37℃and 39℃of the treatment group were significantly lower than those of the control group(P<0.05).However,the catalase concentration in thawing at 37℃and 39℃of the treatment group was not significantly different than the control group(P>0.05).Conclusions:Higher quality post-thawing Boer buck semen is achieved by adding 1μg/mL of chitosan nanoparticles of green tea extract to the skimmed egg yolk diluent and thawing at 39℃.

Extraction, Production and Quality Evaluation of Margarine from Oil Extracted from Waste Biomass Peels of Avocado and Virgin Coconut Oil, Using Chitosan from Reared Shells as Preservative

The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activities. The adverse health effect associated with the consumption of saturated lipid based foods has ignited research on reformulation of lipid based foods to eliminate Trans Fatty Acids (TFAs). This study was thus aimed at the extraction and characterization of oil from Avocado Peels (APO) and evaluation of the quality of margarine produced from it. Five verities of pear were used for oil extraction by soxhlet method and physiochemical, oxidative, functional and antioxidant characterization was done. Margarines were formulated using a central composite design using oil blends of APO and Virgin Coconut Oil (VCO) with an oil ratio of 10:90, 40:60, 70:30 respectively, varied blending speed, blending time, and chitosan concentration. Samples were characterized and the effect of process parameters on the physiochemical and functional properties of the margarine studied. Optimized conditions were used to produce samples for sensory evaluation. Color, spreadability, aroma, taste and general acceptability was evaluated using ranking difference test. The results showed that the yield, density, and iodine values of APOs oils ranged from 14.91 ± 0.18 to 11.76 ± 0.46;0.93 ± 0.001 to 0.99 ± 0.1;46.63 ± 1.70 to 52.4 ± 0.63, their acid values, TBA and PV values ranged from 1.42 ± 0.39 to 1.97 ± 0.5;0.11 ± 0.002 to 0.18 ± 0.04;and 2.72 ± 0.14 to 4.43 ± 0.36 respectively, with Brogdon avocado peel variety having the overall best properties prepared blends of trans-free APO margarines showed that increase in APO ratio decreased melting point, increased oxidative stability and reduced moisture content of margarine samples. Chitosan addition leads to decrease moisture content and increase functional properties. VCO lead to increase in phenolic and flavonoid content of the margarines. Samples were spreadable and palatable with R20 being most palatable and the most accepted being R26 with a mean score of 7.07 ± 0.70. Decrease in color intensity increased acceptability. This study therefore demonstrated that avocado peel waste biomass can be valorized by using it as raw material for oil extraction, which can serve as good material for the production of trans-free margarines with good oxidative stability, functional and antioxidant properties.

ZnO Incorporated Acrylamide Grafted Chitosan Based Composite Film for Advanced Wound Healing Applications

This study was carried out to prepare ZnO nanoparticles incorporated acrylamide grafted chitosan composite film for possible biomedical application especially drug loading in wound healing. ZnO nanoparticles were prepared by co-precipitation method from zinc acetate di-hydrate and incorporated in acrylamide grafted chitosan. FT-IR and TGA of the prepared composite film confirmed the successful incorporation of ZnO nanoparticles in the acrylamide-grafted polymer matrix. SEM images showed that the ZnO nanoparticles were homogeneously distributed on the porous matrix of the composite film. Water uptake and buffer uptake analysis revealed that the composite film could hold water and buffer sufficiently, which facilitated the absorption of exudate from the wound site. Amoxicillin was loaded in the prepared composite film and the maximum loading efficiency was found to be 67.33% with drug concentration of 300 ppm. In vitro studies showed greater antimicrobial activity of drug-loaded composite film compared to both pure film and standard antibiotic disc. Finally, the In vivo mouse model showed maximum healing efficiency compared to conventional gauge bandages because the loading of antibiotic in the film produced a synergistic effect and healing time was reduced.

Structure, properties and application to water-soluble coatings of complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole

The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free -NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 2080, 1560, 2055, 40250, and 4001700mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.

Nanocrystals for enhancement of oral bioavailability of poorly water-soluble drugs

Nanocrystals,a carrier-free colloidal delivery system in nano-sized range,is an interesting approach for poorly soluble drugs.Nanocrystals provide special features including enhancement of saturation solubility,dissolution velocity and adhesiveness to surface/cell membranes.Several strategies are applied for nanocrystals production including precipitation,milling,high pressure homogenization and combination methods such as Nano-Edge^(TM),SmartCrystal and Precipitation-lyophilization-homogenization(PLH)technology.For oral administration,many publications reported useful advantages of nanocrystals to improve in vivo performances i.e.pharmacokinetics,pharmacodynamics,safety and targeted delivery which were discussed in this review.Additionally,transformation of nanocrystals to final formulations and future trends of nanocrystals were also described.

Application of ion chromatography to the determination of water-soluble inorganic and organic ions in atmospheric aerosols

A simple, sensitive and convenient ion chromatography(IC) method was established for the simultaneous determination of twelve water-soluble inorganic anions(F -, Cl -, NO - 2, NO - 3, SO 2- 3, SO 2- 4, PO 3- 4), and fifteen water-soluble organic ions(formate, acetate, MSA, oxalate, malonate, succinate, phthalates, etc.) in atmospheric aerosols. The linear concentrations ranged from 0.005 μg/m 3 to 500 μg/m 3(r = 0.999—0.9999). The relative standard deviation(RSD) were 0.43%—2.00% and the detection limits were from 2.7 ng/m 3 to 88 ng/m 3. The proposed method was successfully applied to the simultaneous determination of those inorganic ions and organic ions in PM 2.5 of Beijing.

Adverse effects of metal exposure on chemotaxis towards water-soluble attractants regulated mainly by ASE sensory neuron in nematode Caenorhabditis elegans

Chemotaxis to water-soluble attractants is mainly controlled by ASE sensory neuron whose specification is regulated by che-1 in Caenorhabditis elegans. Our data suggested that exposure to high concentrations of metals, such as Pb, Cu, Ag, and Cr, would result in severe defects of chemotaxis to water-soluble attractants of NaCl, cAMP, and biotin. Moreover, the morphology of ASE neuron structures as observed by relative fluorescent intensities and relative size of fluorescent puncta of cell bodies, relative lengths of sensory endings in ASE neurons, and the expression patterns of che-1 were obviously altered in metal exposed animals when they meanwhile exhibited obvious chemotaxis defects to water-soluble attractants. In addition, the dendrite morphology could be noticeably changed in animals exposed to 150 μmol/L of Pb, Cu, and Ag. Furthermore, we observed significant decreases of chemotaxis to water-soluble attractants in Pb exposed che-1 mutant at concentrations more than 2.5 μmol/L, and in Cu, Ag, and Cr exposed che-1 mutant at concentrations more than 50 μmol/L. Therefore, impairment of the ASE neuron structures and functions may largely contribute to the appearance of chemotaxis defects to water-soluble attractants in metal exposed nematodes.

On-line Measurement of Water-Soluble Ions in Ambient Particles

Combining the system of rapid collection of ambient particles and ion chromatography, the system of rapid collection of fine particles and ion chromatography （RCFP-IC） was established to automatically analyze on-line the concentrations of water-soluble ions in ambient particles. Here, the general scheme of RCFP-IC is described and its basic performance is tested. The detection limit of RCFP-IC for SO4^2-, NO3^-, NO2^-, Cl^- and F- is below 0.3μg m^-3. The collection efficiency of RCFP-IC increases rapidly with increasing sized particles. For particles larger than 300 nm, the collection efficiency approaches 100%. The precision of RCFP-IC is more than 90% over 28 repetitions. The response of RCFP-IC is very sensitive and no obvious cross-pollution is found during measurement. A comparison of RCFP-IC with an integrated filter measurement indicates that the measurement of RCFP-IC is comparable in both laboratory experiments and field observations. The results of the field experiment prove that RCFP-IC is an effective on-line monitoring system and is helpful in source apportionment and pollution episode monitoring.

Preparation of Ultrafine Water-soluble Polymers Nanofiber Mats via Electrospinning

A series of water-soluble polymers such as poly（ethylene oxide）（PEO）, polyacrylamide（PAM） and poly（vinyl pyrrilidone）（PVP） was successfully prepared via the electrospinning of their aqueous solutions without the use of a surfactant. The effects of solution properties on the electrospinning of PEO, PAM and PVP solutions were investigated. The viscosity of the solution, charge density carried by the jet, and the surface tension of the solution are the key factors that influence the morphology and diameter size of the fibers. The viscosity of the solution was measured on a modular compact rheometer. The morphology and the diameter size distribution of the fibers were observed under an environmental scanning electron microscope（ESEM）. The results show that the diameters of the nanofibers electro spun from the solutions of these water soluble polymers were uniform and less than 300 nm.

Effect of kaolin on tensile strength and humidity resistance of a water-soluble potassium carbonate sand core

Water soluble cores(WSCs) have been widely applied in manufacture of complex metal components with hollow configurations or internal channels. However, the WSCs without any additons have low tensile strength and low humidity resistance. The purpose of this study is to prepare a water-soluble potassium carbonate sand core with addition of kaolin by the hot-temping method. The effects of kaolin on tensile strength, humidity resistance, fracture mechanism, as well as the gas evolution and collapsibility of WSCs were investigated. Results show that both the crystal morphology and the fracture mechanism of the inorganic salt are changed under the participation of kaolin, contributing to the increase of the tensile strength and the humidity resistance of the core. With the addition of 3wt.% kaolin, the tensile strength could be increased by a factor of 2, reached 1.50 MPa and the hygroscopic rate could be decreased by 14%, achieved 0.559%(after stored for 8 h), respectively. As the addition amount of kaolin increases from 0wt.% to 3wt.%, the main fracture mechanism changes from a adhesive to a cohesive fracture mechanism. The water-soluble potassium carbonate core obtained has the low gas evolution and excellent collapsibility, which makes it suitable for casting low melting metal with complex cavities and crooked channels.