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|Abstract:||The invention relates to an implant of polymeric material which can release a contraceptive agent for a relatively long time when fitted subcutaneously or locally.|
|Inventor(s):||De Nijs; Hendrik (Oss, NL)|
|Assignee:||Akzo N.V. (Arnhem, NL)|
|Filing Date:||Jun 21, 1990|
|Claims:||1. A method for preparing an implant comprising: |
mixing a core material of ethylene/vinyl acetate copolymer having such a molecular weight that the melt index is greater than 10 grams/10 minutes, and having a vinyl acetate content of at least 20% by weight with a highly active progestogen; and co-axially extruding said mixture with an ethylene/vinyl acetate copolymer having such a molecular weight that the melt index is less than 10 gram/10 minutes and the vinyl acetate content is less than 20% by weight, thereby forming an implant intended for subcutaneous local administration having a core encased with a member having a layer thickness of 50-250 micrometers thus producing a contact layer at the interface of said core and member.
2. The method according to claim 1, wherein the core material comprises an ethylene vinyl acetate copolymer with a melt index between 25 and 30 grams/10 minutes and a vinyl acetate content of greater than 25% by weight.
3. The method according to claim 1, wherein the membrane comprises ethylene vinyl acetate copolymer with a melt index of 8 grams/10 minutes or less, and a vinyl acetate content of less than 20% by weight.
4. The method according to claim 3 further comprising covering the ends of the implant with an inert polymer.
5. The method of claim 4 further comprising coating the entire implant with polysiloxane.
6. The method of claim 1 wherein the highly active progestogen contraceptive substance is selected from the group consisting of 3-keto-desogestrel, levonorgestrel and gestodene.