Background:This study focused on developing and optimizing a self-microemulsifying drug delivery system(SMEDDS)to improve Lafutidine’s solubility and bioavailability,thereby enhancing its effectiveness in treating ga...Background:This study focused on developing and optimizing a self-microemulsifying drug delivery system(SMEDDS)to improve Lafutidine’s solubility and bioavailability,thereby enhancing its effectiveness in treating gastric ulcers.Traditional formulations are less effective due to their limited water solubility and bioavailability.Methods:The study used solubility tests,pseudo-ternary phase diagrams,and central composite design(CCD)to optimize.The formulation was optimized by varying the oil concentration(10–40%)and surfactant/cosurfactant ratio(0.33–3.00),and then tested for droplet size,drug content,emulsification,phase stability,and in vitro dissolution.Results:The study found that the optimized formulation contained 14%Capmul PG 8NF oil,62%Labrasol surfactant,and 24%Tween 80 cosurfactant.This combination generated an average droplet size of 111.02 nm and improved drug release properties.Furthermore,the formulation was stable without phase separation,with a drug content of 88.2–99.8%.Conclusion:SMEDDS significantly improves lafutidine delivery by increasing solubility and absorption,thereby overcoming oral administration challenges.The system quickly formed small droplets in water and released the drug in 15 min.Enhancing lafutidine’s bioavailability may improve its efficacy in treating gastric ulcers,resulting in better patient outcomes and potentially lower dosing frequency.展开更多
Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging f...Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).展开更多
Pharmaceutical pollution is becoming an increasing threat to aquatic environments since inactive compounds do not break down,and the drug products are accumulated in living organisms.The ability of a drug to dissolve ...Pharmaceutical pollution is becoming an increasing threat to aquatic environments since inactive compounds do not break down,and the drug products are accumulated in living organisms.The ability of a drug to dissolve in water(i.e.,LogS)is an important parameter for assessing a drug’s environmental fate,biovailability,and toxicity.LogS is typically measured in a laboratory setting,which can be costly and time-consuming,and does not provide the opportunity to conduct large-scale analyses.This research develops and evaluates machine learning models that can produce LogS estimates and may improve the environmental risk assessments of toxic pharmaceutical pollutants.We used a dataset from the ChEMBL database that contained 8832 molecular compounds.Various data preprocessing and cleaning techniques were applied(i.e.,removing the missing values),we then recorded chemical properties by normalizing and,even,using some feature selection techniques.We evaluated logS with a total of several machine learning and deep learning models,including;linear regression,random forests(RF),support vector machines(SVM),gradient boosting(GBM),and artificial neural networks(ANNs).We assessed model performance using a series of metrics,including root mean square error(RMSE)and mean absolute error(MAE),as well as the coefficient of determination(R^(2)).The findings show that the Least Angle Regression(LAR)model performed the best with an R^(2) value close to 1.0000,confirming high predictive accuracy.The OMP model performed well with good accuracy(R^(2)=0.8727)while remaining computationally cheap,while other models(e.g.,neural networks,random forests)performed well but were too computationally expensive.Finally,to assess the robustness of the results,an error analysis indicated that residuals were evenly distributed around zero,confirming the results from the LAR model.The current research illustrates the potential of AI in anticipating drug solubility,providing support for green pharmaceutical design and environmental risk assessment.Future work should extend predictions to include degradation and toxicity to enhance predictive power and applicability.展开更多
The accurate measurement of magnesium oxide(MgO)solubility in molten fluoride salts is crucial to optimize the electrolytic process for producing high-purity magnesium(Mg)metal from MgO.In this study,the influences of...The accurate measurement of magnesium oxide(MgO)solubility in molten fluoride salts is crucial to optimize the electrolytic process for producing high-purity magnesium(Mg)metal from MgO.In this study,the influences of time,temperature,and composition of molten salts such as magnesium fluoride(MgF_(2))-lithium fluoride(LiF),MgF_(2)-LiF-calcium fluoride(CaF_(2)),and MgF_(2)-LiF-barium fluoride(BaF_(2))on the solubility of MgO were investigated.Before the MgO solubility experiments,electrolytic removal of oxygen ions(O^(2-))in the molten salts was conducted to decrease the oxygen(O)concentration to below 88 ppm.The results showed that the MgO concentrations in the(MgF_(2)-LiF)_(eut),(MgF_(2)-LiF)_(eut)-15 mol%CaF_(2),and(MgF_(2)-LiF)_(eut)-15 mol%BaF_(2) molten salts at 1053 K reached saturation to 0.210 mass%,0.188 mass%,and 0.148 mass%,respectively,after 30 h.Additionally,MgO solubility at 1053 K decreased with increasing concentrations of CaF_(2) or BaF_(2) in the molten salt.However,the MgO solubility in the molten salts increased with increasing temperature,reaching 0.264 mass% in the(MgF_(2)-LiF)eut molten salt at 1203 K.Moreover,increasing the concentration of MgF_(2) in the MgF_(2)-LiF molten salt increased the MgO solubility at 1103 K.This study provides valuable insights into the MgO solubility in molten fluoride salts used for the electrolytic process using MgO feed for the production of Mg metal.展开更多
Accurate prediction of solubility data in the Sodium Chloride-Sodium Sulfate-Water system is essential.It provides theoretical support for salt lake resource development and wastewater treatment technologies.This stud...Accurate prediction of solubility data in the Sodium Chloride-Sodium Sulfate-Water system is essential.It provides theoretical support for salt lake resource development and wastewater treatment technologies.This study proposes an innovative solubility prediction approach.It addresses the limitations of traditional thermodynamic models.This is particularly important when experimental data from various sources contain inconsistencies.Our approach combines the Weighted Local Outlier Factor technique for anomaly detection with a Deep Ensemble Neural Network architecture.This methodology effectively removes local outliers while preserving data distribution integrity,and integrates multiple neural network sub-models to comprehensively capture system features while minimizing individual model biases.Experimental validation demonstrates exceptional prediction performance across temperatures from−20℃to 150℃,achieving a coefficient of determination of 0.989 after Bayesian hyperparameter optimization.This data-driven approach provides more accurate and universally applicable solubility predictions than conventional thermodynamic models,offering theoretical guidance for industrial applications in salt lake resource utilization,separation process optimization,and environmental salt management systems.展开更多
This study aims to develop a low-energy method for extracting high-purity chitosan from shrimp shell waste.Grounded in the principles of waste valorization,the work addresses the need for alternatives to methods of ch...This study aims to develop a low-energy method for extracting high-purity chitosan from shrimp shell waste.Grounded in the principles of waste valorization,the work addresses the need for alternatives to methods of chitosan extraction that rely on heat and generate significant energy costs.The methodology involved a room-temperature chemical process,comprising deproteinization with NaOH and demineralization with HCl.A notable innovation is the application of the xanthoproteic test—used here for the first time in this context—to monitor protein removal,thus enhancing process control.The extracted chitosan was characterized using FT-IR spectroscopy,and its degree of deacetylation was assessed via titration and FT-IR analysis.Solubility in 1%acetic acid and moisture content were also measured.The results revealed a high degree of deacetylation and excellent solubility,confirming the efficiency of the mild process.This approach offers a pathway for converting marine biowaste into a high-value biopolymer.展开更多
In order to increase the solubility of pyrroloquinoline quinone disodium salt(PQQ-NA_(2))in water,PQQ-NA_(2)ionic salts formed by PQQ-NA_(2)with amine compounds had been developed.Amine compounds specifically refered ...In order to increase the solubility of pyrroloquinoline quinone disodium salt(PQQ-NA_(2))in water,PQQ-NA_(2)ionic salts formed by PQQ-NA_(2)with amine compounds had been developed.Amine compounds specifically refered to aminomethyl propanol,tromethamine,and matrine.The PQQ-NA_(2)ionic salts solubility test result showed an increase as high as 24-fold compared to dissolving PQQ-NA_(2)alone.The antioxidant test indicated that the ionic salts exhibited significant antioxidant property.Two PQQ-NA_(2)gel formulations were prepared containing the ionic salts,and the stability test and PQQ-NA_(2)content test indicated that the formulations were stable and the loss rate of PQQ was below 10%.展开更多
Understanding the solubility of supercritical CO_(2)and its mixtures with other fluids at various temperatures and pressures conditions is critical for their applications,such as extraction processes,material design,a...Understanding the solubility of supercritical CO_(2)and its mixtures with other fluids at various temperatures and pressures conditions is critical for their applications,such as extraction processes,material design,and carbon capture.In the present study,the solubility parameters of supercritical CO_(2),H_(2)O,and their mixtures were calculated by molecular dynamics simulations.The results show that the solubility parameters decrease with increasing temperature and increase with increasing pressure and are linearly proportional to the density.Furthermore,the intermolecular interactions,including the hydrogen bonds,significantly affect the solubility parameter of the CO_(2)-H_(2)O system.展开更多
The thermodynamic properties of the most important NaOH-NaAI（OH）4-H20 system in Bayer process for alumina production were investigated. A theoretical model for calculating the equilibrium constant of gibbsite dissol...The thermodynamic properties of the most important NaOH-NaAI（OH）4-H20 system in Bayer process for alumina production were investigated. A theoretical model for calculating the equilibrium constant of gibbsite dissolved in sodium hydroxide solution was proposed. New Pitzer model parameters and mixing parameters for the system NaOH-NaAI（OH）4-H20 were yielded and tested in the temperature range of 298.15-373.15 K. The results show that the proposed model for calculating the equilibrium constant of gibbsite dissolution is applicable and accurate. The obtained Pitzer model parameters of β（0）（NaAl（OH）4）、β（1）（NaAl（OH）4）和CΦ（NaAl（OH）4）,Al（OH）4 for NaAI（OH）4, the binary mixing parameter of θ（OH-Al（OH）4-） with OH-, and the ternary mixing parameter of ψ（Na＋OH-Al（OH）4-） for AI（OH）4- with OH- and Na＋ are temperature-dependent. The prediction of the equilibrium solubility of gibbsite dissolved in sodium hydroxide solution was feasible in the temperature range of 298.15-373.15 K.展开更多
Surface tension of sodium aluminate solution and the contact angle between Al（OH）3 particles and aluminate solution were measured, then the dependence of Al（OH）3 solubility on its particle size was calculated and ...Surface tension of sodium aluminate solution and the contact angle between Al（OH）3 particles and aluminate solution were measured, then the dependence of Al（OH）3 solubility on its particle size was calculated and thus the variation of the critical nucleus sizes was determined based on the Ostwald ripening formula. The results show that the Al（OH）3 solubility in sodium aluminate solution decreases with the increment of particle size, and the critical nucleus sizes increase with the rise of alkali concentration, caustic ratio and precipitation temperature. The results also imply that the presence of small particles in seeded precipitation system is an important factor to limit the depth of precipitation.展开更多
The solubility of zinc oxide in sodium hydroxide solution was measured in a closed polytetrafluoroethylene vessel from 25 to 100 ℃. The ZnO solubility was determined by employing the method of isothermal solution sat...The solubility of zinc oxide in sodium hydroxide solution was measured in a closed polytetrafluoroethylene vessel from 25 to 100 ℃. The ZnO solubility was determined by employing the method of isothermal solution saturation. The results show that only ZnO solid exists in the equilibrium state in the low concentration alkali regions, and the solubility of zinc oxide is almost invariable with temperature. With the increase of alkali concentration, equilibrium solid turns from ZnO to NaZn（OH）3 suddenly, this mutation is called invariant point. The alkali concentration of the invariant points increases with increasing temperature, but the solubility of NaZn（OH）3 decreases with increasing alkali concentration at the same temperature. At the same Na2O concentration, the higher the temperature is, the higher the solubility of NaZn（OH）3 is.展开更多
The effect of various concentrations of 2-hydroxypropyl-β-cyclodextrin （HP-β-CD） on the solubility of dihydroartemisinin （DHA） in aqueous solution at different pHs was investigated. The influence of different co...The effect of various concentrations of 2-hydroxypropyl-β-cyclodextrin （HP-β-CD） on the solubility of dihydroartemisinin （DHA） in aqueous solution at different pHs was investigated. The influence of different concentrations of 2-hydroxypropyl-β- eyclodextrin on the stability of dihydroartemisinin at 50, 60, 70 and 80 ℃ was also studied. Inclusion complex of dihydroartemisinin with 2-hydroxypropyl-β-cyclodextrin was prepared and characterized by X-ray diffraction and differential scanning calorimetry. The 2-hydroxypropyl-β-cyclodextrin effectively inhibited the hydrolysis of dihydroartemisinin and greatly increased its solubility. Furthermore, we showed that the higher concentrations of 2-hydroxypropyl-β-cyclodextrin, the better stability and solubility of dihydroartemisinin. When the temperature was increased, the stability of dihydroartemisinin decreased. Our results indicated that 2-hydroxypropyl-β-cyclodextrin can be used as a stabilizer and solubilizer of dihydroartemisinin.展开更多
文摘Background:This study focused on developing and optimizing a self-microemulsifying drug delivery system(SMEDDS)to improve Lafutidine’s solubility and bioavailability,thereby enhancing its effectiveness in treating gastric ulcers.Traditional formulations are less effective due to their limited water solubility and bioavailability.Methods:The study used solubility tests,pseudo-ternary phase diagrams,and central composite design(CCD)to optimize.The formulation was optimized by varying the oil concentration(10–40%)and surfactant/cosurfactant ratio(0.33–3.00),and then tested for droplet size,drug content,emulsification,phase stability,and in vitro dissolution.Results:The study found that the optimized formulation contained 14%Capmul PG 8NF oil,62%Labrasol surfactant,and 24%Tween 80 cosurfactant.This combination generated an average droplet size of 111.02 nm and improved drug release properties.Furthermore,the formulation was stable without phase separation,with a drug content of 88.2–99.8%.Conclusion:SMEDDS significantly improves lafutidine delivery by increasing solubility and absorption,thereby overcoming oral administration challenges.The system quickly formed small droplets in water and released the drug in 15 min.Enhancing lafutidine’s bioavailability may improve its efficacy in treating gastric ulcers,resulting in better patient outcomes and potentially lower dosing frequency.
文摘Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).
文摘Pharmaceutical pollution is becoming an increasing threat to aquatic environments since inactive compounds do not break down,and the drug products are accumulated in living organisms.The ability of a drug to dissolve in water(i.e.,LogS)is an important parameter for assessing a drug’s environmental fate,biovailability,and toxicity.LogS is typically measured in a laboratory setting,which can be costly and time-consuming,and does not provide the opportunity to conduct large-scale analyses.This research develops and evaluates machine learning models that can produce LogS estimates and may improve the environmental risk assessments of toxic pharmaceutical pollutants.We used a dataset from the ChEMBL database that contained 8832 molecular compounds.Various data preprocessing and cleaning techniques were applied(i.e.,removing the missing values),we then recorded chemical properties by normalizing and,even,using some feature selection techniques.We evaluated logS with a total of several machine learning and deep learning models,including;linear regression,random forests(RF),support vector machines(SVM),gradient boosting(GBM),and artificial neural networks(ANNs).We assessed model performance using a series of metrics,including root mean square error(RMSE)and mean absolute error(MAE),as well as the coefficient of determination(R^(2)).The findings show that the Least Angle Regression(LAR)model performed the best with an R^(2) value close to 1.0000,confirming high predictive accuracy.The OMP model performed well with good accuracy(R^(2)=0.8727)while remaining computationally cheap,while other models(e.g.,neural networks,random forests)performed well but were too computationally expensive.Finally,to assess the robustness of the results,an error analysis indicated that residuals were evenly distributed around zero,confirming the results from the LAR model.The current research illustrates the potential of AI in anticipating drug solubility,providing support for green pharmaceutical design and environmental risk assessment.Future work should extend predictions to include degradation and toxicity to enhance predictive power and applicability.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)(Project No.:20024463)and(No.RS-2025-04442986)funded by the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Koreathe support of the Institute of Engineering Research at Seoul National University for providing research facilities for this study.
文摘The accurate measurement of magnesium oxide(MgO)solubility in molten fluoride salts is crucial to optimize the electrolytic process for producing high-purity magnesium(Mg)metal from MgO.In this study,the influences of time,temperature,and composition of molten salts such as magnesium fluoride(MgF_(2))-lithium fluoride(LiF),MgF_(2)-LiF-calcium fluoride(CaF_(2)),and MgF_(2)-LiF-barium fluoride(BaF_(2))on the solubility of MgO were investigated.Before the MgO solubility experiments,electrolytic removal of oxygen ions(O^(2-))in the molten salts was conducted to decrease the oxygen(O)concentration to below 88 ppm.The results showed that the MgO concentrations in the(MgF_(2)-LiF)_(eut),(MgF_(2)-LiF)_(eut)-15 mol%CaF_(2),and(MgF_(2)-LiF)_(eut)-15 mol%BaF_(2) molten salts at 1053 K reached saturation to 0.210 mass%,0.188 mass%,and 0.148 mass%,respectively,after 30 h.Additionally,MgO solubility at 1053 K decreased with increasing concentrations of CaF_(2) or BaF_(2) in the molten salt.However,the MgO solubility in the molten salts increased with increasing temperature,reaching 0.264 mass% in the(MgF_(2)-LiF)eut molten salt at 1203 K.Moreover,increasing the concentration of MgF_(2) in the MgF_(2)-LiF molten salt increased the MgO solubility at 1103 K.This study provides valuable insights into the MgO solubility in molten fluoride salts used for the electrolytic process using MgO feed for the production of Mg metal.
基金support of the Natural Science Foundation of Qinghai Province of China(2024-ZJ-940)Qinghai University Research Ability Enhancement Project(2025KTST02)are greatly appreciated.
文摘Accurate prediction of solubility data in the Sodium Chloride-Sodium Sulfate-Water system is essential.It provides theoretical support for salt lake resource development and wastewater treatment technologies.This study proposes an innovative solubility prediction approach.It addresses the limitations of traditional thermodynamic models.This is particularly important when experimental data from various sources contain inconsistencies.Our approach combines the Weighted Local Outlier Factor technique for anomaly detection with a Deep Ensemble Neural Network architecture.This methodology effectively removes local outliers while preserving data distribution integrity,and integrates multiple neural network sub-models to comprehensively capture system features while minimizing individual model biases.Experimental validation demonstrates exceptional prediction performance across temperatures from−20℃to 150℃,achieving a coefficient of determination of 0.989 after Bayesian hyperparameter optimization.This data-driven approach provides more accurate and universally applicable solubility predictions than conventional thermodynamic models,offering theoretical guidance for industrial applications in salt lake resource utilization,separation process optimization,and environmental salt management systems.
文摘This study aims to develop a low-energy method for extracting high-purity chitosan from shrimp shell waste.Grounded in the principles of waste valorization,the work addresses the need for alternatives to methods of chitosan extraction that rely on heat and generate significant energy costs.The methodology involved a room-temperature chemical process,comprising deproteinization with NaOH and demineralization with HCl.A notable innovation is the application of the xanthoproteic test—used here for the first time in this context—to monitor protein removal,thus enhancing process control.The extracted chitosan was characterized using FT-IR spectroscopy,and its degree of deacetylation was assessed via titration and FT-IR analysis.Solubility in 1%acetic acid and moisture content were also measured.The results revealed a high degree of deacetylation and excellent solubility,confirming the efficiency of the mild process.This approach offers a pathway for converting marine biowaste into a high-value biopolymer.
文摘In order to increase the solubility of pyrroloquinoline quinone disodium salt(PQQ-NA_(2))in water,PQQ-NA_(2)ionic salts formed by PQQ-NA_(2)with amine compounds had been developed.Amine compounds specifically refered to aminomethyl propanol,tromethamine,and matrine.The PQQ-NA_(2)ionic salts solubility test result showed an increase as high as 24-fold compared to dissolving PQQ-NA_(2)alone.The antioxidant test indicated that the ionic salts exhibited significant antioxidant property.Two PQQ-NA_(2)gel formulations were prepared containing the ionic salts,and the stability test and PQQ-NA_(2)content test indicated that the formulations were stable and the loss rate of PQQ was below 10%.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFE0117200)the National Natural Science Foundation of China(Grant No.41977304).
文摘Understanding the solubility of supercritical CO_(2)and its mixtures with other fluids at various temperatures and pressures conditions is critical for their applications,such as extraction processes,material design,and carbon capture.In the present study,the solubility parameters of supercritical CO_(2),H_(2)O,and their mixtures were calculated by molecular dynamics simulations.The results show that the solubility parameters decrease with increasing temperature and increase with increasing pressure and are linearly proportional to the density.Furthermore,the intermolecular interactions,including the hydrogen bonds,significantly affect the solubility parameter of the CO_(2)-H_(2)O system.
基金Project (2005CB6237) supported by the National Basic Research Program of China
文摘The thermodynamic properties of the most important NaOH-NaAI（OH）4-H20 system in Bayer process for alumina production were investigated. A theoretical model for calculating the equilibrium constant of gibbsite dissolved in sodium hydroxide solution was proposed. New Pitzer model parameters and mixing parameters for the system NaOH-NaAI（OH）4-H20 were yielded and tested in the temperature range of 298.15-373.15 K. The results show that the proposed model for calculating the equilibrium constant of gibbsite dissolution is applicable and accurate. The obtained Pitzer model parameters of β（0）（NaAl（OH）4）、β（1）（NaAl（OH）4）和CΦ（NaAl（OH）4）,Al（OH）4 for NaAI（OH）4, the binary mixing parameter of θ（OH-Al（OH）4-） with OH-, and the ternary mixing parameter of ψ（Na＋OH-Al（OH）4-） for AI（OH）4- with OH- and Na＋ are temperature-dependent. The prediction of the equilibrium solubility of gibbsite dissolved in sodium hydroxide solution was feasible in the temperature range of 298.15-373.15 K.
基金Project(51274242)supported by the National Natural Science Foundation of China
文摘Surface tension of sodium aluminate solution and the contact angle between Al（OH）3 particles and aluminate solution were measured, then the dependence of Al（OH）3 solubility on its particle size was calculated and thus the variation of the critical nucleus sizes was determined based on the Ostwald ripening formula. The results show that the Al（OH）3 solubility in sodium aluminate solution decreases with the increment of particle size, and the critical nucleus sizes increase with the rise of alkali concentration, caustic ratio and precipitation temperature. The results also imply that the presence of small particles in seeded precipitation system is an important factor to limit the depth of precipitation.
基金Project (2007CB613603) supported by the National Basic Research Program of China
文摘The solubility of zinc oxide in sodium hydroxide solution was measured in a closed polytetrafluoroethylene vessel from 25 to 100 ℃. The ZnO solubility was determined by employing the method of isothermal solution saturation. The results show that only ZnO solid exists in the equilibrium state in the low concentration alkali regions, and the solubility of zinc oxide is almost invariable with temperature. With the increase of alkali concentration, equilibrium solid turns from ZnO to NaZn（OH）3 suddenly, this mutation is called invariant point. The alkali concentration of the invariant points increases with increasing temperature, but the solubility of NaZn（OH）3 decreases with increasing alkali concentration at the same temperature. At the same Na2O concentration, the higher the temperature is, the higher the solubility of NaZn（OH）3 is.
文摘The effect of various concentrations of 2-hydroxypropyl-β-cyclodextrin （HP-β-CD） on the solubility of dihydroartemisinin （DHA） in aqueous solution at different pHs was investigated. The influence of different concentrations of 2-hydroxypropyl-β- eyclodextrin on the stability of dihydroartemisinin at 50, 60, 70 and 80 ℃ was also studied. Inclusion complex of dihydroartemisinin with 2-hydroxypropyl-β-cyclodextrin was prepared and characterized by X-ray diffraction and differential scanning calorimetry. The 2-hydroxypropyl-β-cyclodextrin effectively inhibited the hydrolysis of dihydroartemisinin and greatly increased its solubility. Furthermore, we showed that the higher concentrations of 2-hydroxypropyl-β-cyclodextrin, the better stability and solubility of dihydroartemisinin. When the temperature was increased, the stability of dihydroartemisinin decreased. Our results indicated that 2-hydroxypropyl-β-cyclodextrin can be used as a stabilizer and solubilizer of dihydroartemisinin.
