| abstract |
A solid mixture of a degradable polymer (B) in which an active agent loaded microporous powder or granulate form polymer (A) is uniformly dispersed. The active agent loaded polymer (A) is distributed throughout said polymer matrix by simple stirring of polymer (A) in a melt of polymer (B) or through kneading of polymer (A) and (B) or through coextrusion of polymers (A) and (B). The preparation of powder or granulate form structures and of shaped solid structures is possible according to the invention. The speed of degradation of polymer (B) in the selected surrounding environment, for instance, a human or animal body, determines the release rate of the active agent so that the release takes place in accordance with a velocity rule zero arrangement and is a constant or invariable. In this manner the release of the active agent into the surrounding environment or mileau is controlled and maintained according to predetermined conditions. The solid structures of the invention are suitable for the release of solid and liquid active agents such as medicaments, hormones, fertilizers, pesiticides and the like. Preferably, the polymers used are based on polylactides. |