Active agent containing solid structures for prolonged release of active agents

• US 5,248,700 A
• Filed: 04/21/1989
• Issued: 09/28/1993
• Est. Priority Date: 05/14/1982
• Status: Expired due to Term

• Current Assignee: Membrana GmbH (Asahi Kasei Corporation)
• Original Assignee: AKZO NV (Nouryon BV)
• Inventors: Lance, Wolfgang
• Primary Examiner(s): Kulkosky, Peter F.
• Application Number:
  US07/341,929
• Time in Patent Office: 1,621 Days
• Field of Search: 424/78, 424/426, 424/428, 424/469, 424/470, 514/772.3
• US Class Current: 514/772.3
• CPC Class Codes: A01N 25/10 Macromolecular compounds
• CPC Class Codes: A61K 9/204 Polyesters, e.g. poly(lactide-co-glycolide)
• CPC Class Codes: A61K 9/2077 Tablets comprising drug-containing microparticles in a substantial amount of supporting matrix; Multiparticulate tablets
• CPC Class Codes: C05G 5/40 Fertilisers incorporated into a matrix

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.

Claims

1. An active agent containing solid structure adapted for prolonged release of said active agent, said active agent containing solid structure comprising a matrix of a degradable polymer (B) and a microporous powder form polymer (A) loaded with said active agent, said microporous powder form polymer (A) being uniformly distributed in said matrix.

2. An active agent containing solid structure according to claim 1, wherein said polymer (A) is also degradable.

3. An active agent containing solid structure according to claim 2 wherein the degradation velocity of said polymer (A) is less than the degradation velocity of said matrix polymer (B).

4. An active agent containing solid structure according to claim 2 wherein as said degradable polymer (B) a copolymer of lactic acid is used.

5. An active agent containing solid structure according to claim 1, wherein the microporous powder form polymer (A) is loaded with other active agents different from said active agent.

6. An active agent containing solid structure according to claim 1, wherein said active agent is selected from the group consisting of medicinal agents, hormones, enzymes, vitamins, anti-microbial agents, fertilizers, pesticides, plant growth regulating agents and fragrances.

7. Method of controllably dispensing an active agent at a predetermined location so as to provide a prolonged release of the active agent, said method comprising introducing an active agent containing solid structure according to claim 1 which contains the active agent into the predetermined location.