The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone(PVP)-polyethylene glycol(PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of...The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone(PVP)-polyethylene glycol(PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of the drug. A number of silymarin-laden polymeric formulations were fabricated with different quantities of PVP K-30 and PEG 6000 by the solvent-evaporation method. The effect of PVP K-30 and PEG 6000 on the aqueous solubility and dissolution rate was investigated. The optimized formulation and its constituents were characterized using powder X-ray diffraction(PXRD), differential scanning calorimetry(DSC), scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR) techniques. Both the PEG 6000 and PVP K-30 positively affected the aqueous solubility and dissolution rate of the drug. In particular, a formulation consisting of silymarin, PVP K-30 and PEG 6000(0.25/1.5/1.5, w/w/w) furnished the highest solubility(24.3972.95 mg/mL) and an excellent dissolution profile( $100% in 40 min). The solubility enhancement with this formulation was $ 1150-fold as compared to plain silymarin powder. Moreover, all the constituents existed in the amorphous state in this silymarin-laden PVP-PEG polymeric composite. Accordingly, this formulation might be a promising tool to administer silymarin with an enhanced effect via the oral route.展开更多
Using the industrial technologies of rubber latex irradiation,preparation of nanoscale silica(SiO2) slurry,mixing irradiated rubber latex with SiO2 slurry,and the spray drying,we have prepared the ultrafine fully-vulc...Using the industrial technologies of rubber latex irradiation,preparation of nanoscale silica(SiO2) slurry,mixing irradiated rubber latex with SiO2 slurry,and the spray drying,we have prepared the ultrafine fully-vulcanized powder carboxyl styrene-butadiene rubber(UFPCSBR)/SiO2 nanocompound powder,in which the SiO2 particles and UFPCSBR particles are isolated and stuck each other.When the UFPCSBR/SiO2 nanocompound powder is mixed with crude rubber,the UFPCSBR particles are dispersed well in rubber matrix because of their good compatibility,then the SiO2 particles are also dispersed well in rubber matrix because of the carrier nature of the UFPCSBR particles during the mixing procedure,and the novel rubber/UFPCSBR/SiO2 nanocomposites are fabricated.Compared with the rubber composites prepared by mixing the crude rubber with the UFPCSBR powder and SiO2 powder one after the other,the novel UFPCSBR/SiO2 nanocompound modified rubber/UFPCSBR/SiO2 nanocomposites have better abrasion resistance,higher tensile strength and tear strength,and lower heat build-up data.Noteworthily,the tanδ-temperature curve of the novel rubber/UFPCSBR/SiO2 nanocomposites has the second tanδ peak due to the newly generated boundary layer surrounding the SiO2 particles,increasing the tanδ values in the temperature range of 0-20℃,which is very important to the research of green tyre tread.展开更多
A series of cationic water-borne polyurethane(CWPU) was synthesized from isophorone diisocyanate (IPDI), polyneopentanediol adipate (P756) and hydrophilic N-methyl dihydroxyethyl amine (N-MDEA) by using the one-step p...A series of cationic water-borne polyurethane(CWPU) was synthesized from isophorone diisocyanate (IPDI), polyneopentanediol adipate (P756) and hydrophilic N-methyl dihydroxyethyl amine (N-MDEA) by using the one-step process. Phase inversion of the cationic water-borne polyurethane was established by tracing the change of conductivity and speed of stirrer during the dispersion process.The conductivity of CWPU increased to a maximum, and then decreased to a stabe value.This result showed that the enrichment of partial anion and the gemination of ion occurred successively during the process of phase inversion.Conductivity kept stable after the Stern layer of the CWPU colloid particles were formed. The effects of dispersion temperature and the amount of N-MDEA on the particle size of CWPU were discussed. The particle size and polydispersity of CWPU were decreased with higher dispersion temperature and increasing amount of hydrophilic chain-extender. There existed optimal dispersion temperature and amount of chain-extender of the cationic polyurethane during the dispersion process. The DSC and DMA data of the cast film of CWPU showed that water could enter the partially disrupted ordered structure of the CWPU hard segment when phase inversion occurred at an appropriate temperature, and the stable, smaller particle size and polydisperse of the CWPU could be obtained.展开更多
文摘The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone(PVP)-polyethylene glycol(PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of the drug. A number of silymarin-laden polymeric formulations were fabricated with different quantities of PVP K-30 and PEG 6000 by the solvent-evaporation method. The effect of PVP K-30 and PEG 6000 on the aqueous solubility and dissolution rate was investigated. The optimized formulation and its constituents were characterized using powder X-ray diffraction(PXRD), differential scanning calorimetry(DSC), scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR) techniques. Both the PEG 6000 and PVP K-30 positively affected the aqueous solubility and dissolution rate of the drug. In particular, a formulation consisting of silymarin, PVP K-30 and PEG 6000(0.25/1.5/1.5, w/w/w) furnished the highest solubility(24.3972.95 mg/mL) and an excellent dissolution profile( $100% in 40 min). The solubility enhancement with this formulation was $ 1150-fold as compared to plain silymarin powder. Moreover, all the constituents existed in the amorphous state in this silymarin-laden PVP-PEG polymeric composite. Accordingly, this formulation might be a promising tool to administer silymarin with an enhanced effect via the oral route.
基金supported by the National Natural Science Foundation of China (Grant No. 50873049)National High Technology Research and Development Program of China ("863" Program) (Grant No. 2009AA-03Z338)+1 种基金Shandong Young Scientists Encouragement Foundation (Grant No. 2007BS04038)the Scientific Research Foundation of Shandong Education Department (Grant No. J07YA12)
文摘Using the industrial technologies of rubber latex irradiation,preparation of nanoscale silica(SiO2) slurry,mixing irradiated rubber latex with SiO2 slurry,and the spray drying,we have prepared the ultrafine fully-vulcanized powder carboxyl styrene-butadiene rubber(UFPCSBR)/SiO2 nanocompound powder,in which the SiO2 particles and UFPCSBR particles are isolated and stuck each other.When the UFPCSBR/SiO2 nanocompound powder is mixed with crude rubber,the UFPCSBR particles are dispersed well in rubber matrix because of their good compatibility,then the SiO2 particles are also dispersed well in rubber matrix because of the carrier nature of the UFPCSBR particles during the mixing procedure,and the novel rubber/UFPCSBR/SiO2 nanocomposites are fabricated.Compared with the rubber composites prepared by mixing the crude rubber with the UFPCSBR powder and SiO2 powder one after the other,the novel UFPCSBR/SiO2 nanocompound modified rubber/UFPCSBR/SiO2 nanocomposites have better abrasion resistance,higher tensile strength and tear strength,and lower heat build-up data.Noteworthily,the tanδ-temperature curve of the novel rubber/UFPCSBR/SiO2 nanocomposites has the second tanδ peak due to the newly generated boundary layer surrounding the SiO2 particles,increasing the tanδ values in the temperature range of 0-20℃,which is very important to the research of green tyre tread.
文摘A series of cationic water-borne polyurethane(CWPU) was synthesized from isophorone diisocyanate (IPDI), polyneopentanediol adipate (P756) and hydrophilic N-methyl dihydroxyethyl amine (N-MDEA) by using the one-step process. Phase inversion of the cationic water-borne polyurethane was established by tracing the change of conductivity and speed of stirrer during the dispersion process.The conductivity of CWPU increased to a maximum, and then decreased to a stabe value.This result showed that the enrichment of partial anion and the gemination of ion occurred successively during the process of phase inversion.Conductivity kept stable after the Stern layer of the CWPU colloid particles were formed. The effects of dispersion temperature and the amount of N-MDEA on the particle size of CWPU were discussed. The particle size and polydispersity of CWPU were decreased with higher dispersion temperature and increasing amount of hydrophilic chain-extender. There existed optimal dispersion temperature and amount of chain-extender of the cationic polyurethane during the dispersion process. The DSC and DMA data of the cast film of CWPU showed that water could enter the partially disrupted ordered structure of the CWPU hard segment when phase inversion occurred at an appropriate temperature, and the stable, smaller particle size and polydisperse of the CWPU could be obtained.
基金Supported by the National Natural Science Foundation of China(5097806750778049+3 种基金51121062)the Ministry of Science and Technology of China(2009AA06Z3102009ZX074240052009ZX07424-006)
