The aim of this study was to design porous matrix beads for floating drug delivery using enteric polymer, Eudragit~? L and various amounts of waxes(0, 0.1, 0.5, 1, 2 and 3% w/w). In this study, wax containing cetyl al...The aim of this study was to design porous matrix beads for floating drug delivery using enteric polymer, Eudragit~? L and various amounts of waxes(0, 0.1, 0.5, 1, 2 and 3% w/w). In this study, wax containing cetyl alcohol and white petrolatum was utilized to produce pores using a wax removal technique. To prepare the beads, Eudragit~? L, metronidazole and wax were dissolved in acetone and then extruded into dichloromethane. The effect of the amount of wax on the floating and drug release behavior of the Eudragit~? L beads was determined.After the extruded product was immersed in dichloromethane, wax dissolved out from the formed beads, resulting in a porous structure. The prepared beads could float in simulated gastric fluid for more than 10 hours. Different amounts of wax had an effect on the drug release. We found that when the percentage of wax increased, the drug release was higher while the beads remained floating. The results suggest that Eudragit~? L beads could be used as a carrier for an intragastric floating drug delivery system.展开更多
Fly ash floating bead（FAFB） was modified by the nonionic surfactant polyethylene glycol（PEG） under various concentrations to improve its hydrophobility,and then PEG modified FAFB composited with polyaniline（FAFB-...Fly ash floating bead（FAFB） was modified by the nonionic surfactant polyethylene glycol（PEG） under various concentrations to improve its hydrophobility,and then PEG modified FAFB composited with polyaniline（FAFB-PEG/PAn） by emulsion polymerization method using different feed ratios of FAFBPEG.The chemical structure,phase structure,microstructure,conductivity,and dielectric properties were studied by FT-IR,XRD,SEM,four-probe technique,and LCR digital bridge,respectively.It was demonstrated that the optimal concentration of PEG was 1 mol/L and the corresponding grafting ratio was 1.42%.The phase structure of FAFB was not destroyed after modification by PEG,while the surface became smoother and could be coated by PAn successfully according to SEM technique.Compared to that of dodecylbenzenesulfonic acid doped PAn（PAn-DBSA）,the conductivity of FAFB-PEG/PAn was decreased by 10-100 times after introduction of various amounts of FAFB-PEG,especially the value could be decreased to 0.01 S cm^-1 if 50 wt%of FAFBPEG was provided.Additionally,the dielectric constant and loss factor of FAFB-PEG/PAn composites gradually decreased with increasing amount of FAFB-PEG in the frequency range of 100 KHz-2 MHz,namely,the dielectric constant could be still kept at 500 and correspondingly the loss factor decreased to 4.7 at 100 KHz if50 wt%of FAFB-PEG was provided.The leaking current phenomenon derived from PAn-DBSA could also be weakened by FAFB-PEG.展开更多
基金the Faculty of Pharmacy, Silpakorn University for financial support
文摘The aim of this study was to design porous matrix beads for floating drug delivery using enteric polymer, Eudragit~? L and various amounts of waxes(0, 0.1, 0.5, 1, 2 and 3% w/w). In this study, wax containing cetyl alcohol and white petrolatum was utilized to produce pores using a wax removal technique. To prepare the beads, Eudragit~? L, metronidazole and wax were dissolved in acetone and then extruded into dichloromethane. The effect of the amount of wax on the floating and drug release behavior of the Eudragit~? L beads was determined.After the extruded product was immersed in dichloromethane, wax dissolved out from the formed beads, resulting in a porous structure. The prepared beads could float in simulated gastric fluid for more than 10 hours. Different amounts of wax had an effect on the drug release. We found that when the percentage of wax increased, the drug release was higher while the beads remained floating. The results suggest that Eudragit~? L beads could be used as a carrier for an intragastric floating drug delivery system.
基金Funded by National Natural Science Foundation of China(No.51204131)
文摘Fly ash floating bead（FAFB） was modified by the nonionic surfactant polyethylene glycol（PEG） under various concentrations to improve its hydrophobility,and then PEG modified FAFB composited with polyaniline（FAFB-PEG/PAn） by emulsion polymerization method using different feed ratios of FAFBPEG.The chemical structure,phase structure,microstructure,conductivity,and dielectric properties were studied by FT-IR,XRD,SEM,four-probe technique,and LCR digital bridge,respectively.It was demonstrated that the optimal concentration of PEG was 1 mol/L and the corresponding grafting ratio was 1.42%.The phase structure of FAFB was not destroyed after modification by PEG,while the surface became smoother and could be coated by PAn successfully according to SEM technique.Compared to that of dodecylbenzenesulfonic acid doped PAn（PAn-DBSA）,the conductivity of FAFB-PEG/PAn was decreased by 10-100 times after introduction of various amounts of FAFB-PEG,especially the value could be decreased to 0.01 S cm^-1 if 50 wt%of FAFBPEG was provided.Additionally,the dielectric constant and loss factor of FAFB-PEG/PAn composites gradually decreased with increasing amount of FAFB-PEG in the frequency range of 100 KHz-2 MHz,namely,the dielectric constant could be still kept at 500 and correspondingly the loss factor decreased to 4.7 at 100 KHz if50 wt%of FAFB-PEG was provided.The leaking current phenomenon derived from PAn-DBSA could also be weakened by FAFB-PEG.
