Aim To prepare the prolonged-released microspheres of mefformin hydrochloride. Methods Ion-exchange resin-drug mefformin hydrochloride complexes were prepared as core materials, and followed by coating using ethylcell...Aim To prepare the prolonged-released microspheres of mefformin hydrochloride. Methods Ion-exchange resin-drug mefformin hydrochloride complexes were prepared as core materials, and followed by coating using ethylcellulose （EC） by the emulsion solvent diffusion technique. The release rate of mefformin from the microcapsules was highly dependent on the encapsulating formulation, thus being used as an index for formulation screening. Orthogonal experiments were performed to optimize the coating formulation. Results The final chosen formulation for coating of mefformin microcapsules were as follows： （ 1 ） the ratio of EC （20cps） to EC （45cps） was 50：50; （2） the ratio of plasticizer to coating materials was 20% ;and （3） the ratio of resin-mefformin complexes to coating materials was 5 ： 1. Conclusion The prolonged release microspheres of mefformin hydrochloride were successfully prepared.展开更多
Single hydration of the gas phase F^-+CH3I→CH3F reaction allows to probe solvent effects on a fundamental nucleophilic substitution reaction.At the same time,the addition of a solvent molecule opens alternative produ...Single hydration of the gas phase F^-+CH3I→CH3F reaction allows to probe solvent effects on a fundamental nucleophilic substitution reaction.At the same time,the addition of a solvent molecule opens alternative product channels.Here,we present crossed beam imaging results on the dynamics of the F^-(H2O)+CH3I→[FCH3I]^-+H2O ligand exchange pathway at collision energies between 0.3 and 2.6 eV.Product kinetic energies are constrained by the stability requirement of the weakly bound product complexes.This implies substantial internal excitation of the water molecule and disfavors effcient energy redistribution in an intermediate complex,which is reflected by the suppression of low kinetic energies as collision energy increases.At 0.3 eV,internal nucleophilic displacement is important and is discussed in light of the competing nucleophilic substitution pathways that form I^- and I^-(H2O).展开更多
the desalting property of ion-exchange resins in organic solventis reported by using potassium acetate as a model compound. Theexperimental results show that solvability of the solvent, stirringspeed, and temperature ...the desalting property of ion-exchange resins in organic solventis reported by using potassium acetate as a model compound. Theexperimental results show that solvability of the solvent, stirringspeed, and temperature are the factors which influence theion-exchange rate. The increase of solvability, stirring speed andtemperature will speed up the ion-exchange process.展开更多
Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with...Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.展开更多
Tin-doped Indium Oxide （ITO） has been successfully prepared via solvothermal method with a mixture of Indium（Ill） acetylacetonate and Tin（IV） bis（acetylacetonate）dichioride in oleyamine solvent under the condi...Tin-doped Indium Oxide （ITO） has been successfully prepared via solvothermal method with a mixture of Indium（Ill） acetylacetonate and Tin（IV） bis（acetylacetonate）dichioride in oleyamine solvent under the condition of the different reaction time from 12 h to 48 h for the first time. The morphology, phase composition and particle size of the ITO powder were characterized by TEM and XRD. Two significant properties required for ITO samples to become noncarbon support for Pt in PEMFCs including specific surface area and electrical conductivity were studied.展开更多
文摘Aim To prepare the prolonged-released microspheres of mefformin hydrochloride. Methods Ion-exchange resin-drug mefformin hydrochloride complexes were prepared as core materials, and followed by coating using ethylcellulose （EC） by the emulsion solvent diffusion technique. The release rate of mefformin from the microcapsules was highly dependent on the encapsulating formulation, thus being used as an index for formulation screening. Orthogonal experiments were performed to optimize the coating formulation. Results The final chosen formulation for coating of mefformin microcapsules were as follows： （ 1 ） the ratio of EC （20cps） to EC （45cps） was 50：50; （2） the ratio of plasticizer to coating materials was 20% ;and （3） the ratio of resin-mefformin complexes to coating materials was 5 ： 1. Conclusion The prolonged release microspheres of mefformin hydrochloride were successfully prepared.
基金support by a Hertha-Firnberg fellowship of the Austrian Science Fund (T962-N34).
文摘Single hydration of the gas phase F^-+CH3I→CH3F reaction allows to probe solvent effects on a fundamental nucleophilic substitution reaction.At the same time,the addition of a solvent molecule opens alternative product channels.Here,we present crossed beam imaging results on the dynamics of the F^-(H2O)+CH3I→[FCH3I]^-+H2O ligand exchange pathway at collision energies between 0.3 and 2.6 eV.Product kinetic energies are constrained by the stability requirement of the weakly bound product complexes.This implies substantial internal excitation of the water molecule and disfavors effcient energy redistribution in an intermediate complex,which is reflected by the suppression of low kinetic energies as collision energy increases.At 0.3 eV,internal nucleophilic displacement is important and is discussed in light of the competing nucleophilic substitution pathways that form I^- and I^-(H2O).
文摘the desalting property of ion-exchange resins in organic solventis reported by using potassium acetate as a model compound. Theexperimental results show that solvability of the solvent, stirringspeed, and temperature are the factors which influence theion-exchange rate. The increase of solvability, stirring speed andtemperature will speed up the ion-exchange process.
基金Supported by the National Natural Science Foundation of China(No.29876037)and the Natural Science Foundation ofZhejiang Province(No.296068)
文摘Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.
文摘Tin-doped Indium Oxide （ITO） has been successfully prepared via solvothermal method with a mixture of Indium（Ill） acetylacetonate and Tin（IV） bis（acetylacetonate）dichioride in oleyamine solvent under the condition of the different reaction time from 12 h to 48 h for the first time. The morphology, phase composition and particle size of the ITO powder were characterized by TEM and XRD. Two significant properties required for ITO samples to become noncarbon support for Pt in PEMFCs including specific surface area and electrical conductivity were studied.
