An approximate analytical solution of moving boundary problem for diffusion release of drug from a cylinder polymeric matrix was obtained by use of refined integral method. The release kinetics has been analyzed for n...An approximate analytical solution of moving boundary problem for diffusion release of drug from a cylinder polymeric matrix was obtained by use of refined integral method. The release kinetics has been analyzed for non-erodible matrices with perfect sink condition. The formulas of the moving boundary and the fractional drug release were given. The moving boundary and the fractional drug release have been calculated at various drug loading levels, mid the calculated results were in good agreement with those of experiments. The comparison of the moving boundary in spherical, cylinder, planar matrices has been completed. An approximate formula for estimating the available release time was presented. These results are useful for the clinic experiments. This investigation provides a new theoretical tool for studying the diffusion release of drug from a cylinder polymeric matrix and designing the controlled released drug.展开更多
The interfacial diffusive contaminant（phosphorus） release from permeable sediment layer into overlying water column under a unidirectional unsteady（periodic） flow condition was experimentally measured and analyzed...The interfacial diffusive contaminant（phosphorus） release from permeable sediment layer into overlying water column under a unidirectional unsteady（periodic） flow condition was experimentally measured and analyzed. The experimental results indicate that the gross diffusive contaminant release rate is substantially enhanced as compared to that under a steady flow condition, and this enhancement trend is much more pronounced in an immediate release stage. The interfacial diffusive contaminant release rate tends to increase with the increasing flow velocity, decreasing period and augmenting amplitude for the case of the unsteady flow. The additional interfacial diffusive contaminant release under the unsteady flow condition may be related to the hydrodynamic response of the diffusive boundary layer to the flow unsteadiness of the overlying water, depending upon not only the periodic thickness variation of the diffusive boundary layer immediately above the sediment-water interface modulated by the temporal flow velocity of the overlying water column but also the intensified turbulent mixing between the overlying water and the pore-water within the superficial sediment layer induced by an alternate acceleration/deceleration fluctuation during each period.展开更多
文摘An approximate analytical solution of moving boundary problem for diffusion release of drug from a cylinder polymeric matrix was obtained by use of refined integral method. The release kinetics has been analyzed for non-erodible matrices with perfect sink condition. The formulas of the moving boundary and the fractional drug release were given. The moving boundary and the fractional drug release have been calculated at various drug loading levels, mid the calculated results were in good agreement with those of experiments. The comparison of the moving boundary in spherical, cylinder, planar matrices has been completed. An approximate formula for estimating the available release time was presented. These results are useful for the clinic experiments. This investigation provides a new theoretical tool for studying the diffusion release of drug from a cylinder polymeric matrix and designing the controlled released drug.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11032007,11472168)the Shanghai key Laboratory of mechanics in energy Engineering and Shanghai Program for Innovative Research Team in Universities
文摘The interfacial diffusive contaminant（phosphorus） release from permeable sediment layer into overlying water column under a unidirectional unsteady（periodic） flow condition was experimentally measured and analyzed. The experimental results indicate that the gross diffusive contaminant release rate is substantially enhanced as compared to that under a steady flow condition, and this enhancement trend is much more pronounced in an immediate release stage. The interfacial diffusive contaminant release rate tends to increase with the increasing flow velocity, decreasing period and augmenting amplitude for the case of the unsteady flow. The additional interfacial diffusive contaminant release under the unsteady flow condition may be related to the hydrodynamic response of the diffusive boundary layer to the flow unsteadiness of the overlying water, depending upon not only the periodic thickness variation of the diffusive boundary layer immediately above the sediment-water interface modulated by the temporal flow velocity of the overlying water column but also the intensified turbulent mixing between the overlying water and the pore-water within the superficial sediment layer induced by an alternate acceleration/deceleration fluctuation during each period.
