摘要 |
Polymeric delivery systems for active substances are prepared by suspension polymerization of a porogen and monomer mixture in an immiscible phase, typically an aqueous immiscible phase. By properly controlling the polymerization conditions and percentage of cross-linking, relatively rigid beads are formed having a non-collapsible pore network containing the porogen. The porogen is then extracted from the pore network, and an active substance, such as a UV absorbant, and insect repellant, a steroid, an emollient, or the like, is introduced into the beads. |