| 主权项 |
1. A drug delivery system comprising:
an inner core, comprising (i) a biocompatible fluid component consisting of polyethylene glycol, (ii) a biocompatible solid component dispersed, suspended, or dissolved in the biocompatible fluid component, wherein the biocompatible solid component is poly(dl-lactide-co-glycolide) and is more soluble in the biocompatible fluid component than in physiological fluid, and (iii) at least one agent dispersed, suspended, or dissolved within the inner core, wherein the inner core undergoes a phase change upon contact with a physiological fluid; a first polymer layer, impermeable to the passage of the at least one agent, that covers at least part of but less than 100% of said inner core; and optionally, a second polymer layer that is permeable to the passage of the at least one agent; wherein the release rate of the agent is limited primarily by the portion of the inner core that is covered by the first polymer layer, the physical properties of the core, the dissolution rate of the core or components of the core, the permeability of the second polymer layer, or the solubility of the at least one agent in the physiological fluid immediately surrounding the polymer. |
