| 摘要 |
A composition for controlling the release rate of an agent is presented. The composition includes a hydrophilic first component and a polymeric second component mixed with the hydrophilic first component. The composition remains substantially impermeable until exposure to a hydrophilic solvent that converts sites in the composition that are occupied by the hydrophilic first component to permeation channels for the hydrophilic solvent. The composition may be used for coating a core that contains an agent. When the composition is placed in the hydrophilic solvent, the hydrophilic solvent permeates to the core, dissolves the agent, and releases the agent at a controlled rate through the permeation channels. Where the core contains reactants for a target agent, the hydrohphilic solvent reaches the core and dissolves the reactants to trigger a chemical reaction that produces the target agent. The target agent is released at a controlled rate through the permeation channels.
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