Local system for the release of active principle and process for its manufacture

Abstract

A local system for the release of active principle is described which consists of approximately spherical or rotation symmetrical bodies which are composed essentially of polymethyl methacrylate or polymethyl methacrylate co-methyl acrylate, zirconium dioxide or barium sulphate and one or more pharmaceutical active principles, in particular antibiotics, and which are produced by radical polymerisation, radical polymerisation activators effective in the temperature range of 10-80° C. or residues of these polymerisation activators from the groups of aromatic amines, heavy metal salts and barbiturates not being contained therein. A process for the production of the local system for the release of active principle in the case of which a) a paste is produced by mixing methyl methacrylate, polymethyl methacrylate or poly-methyl methacrylate co-methyl acrylate, zirconium dioxide and/or barium sulphate, one or more pharmaceutical active principles and a thermally decomposing radical initiator, the paste having a viscosity such that it cannot be deformed at room temperature by the effect of gravity; b) the paste is injection moulded by an injection moulding device without heating at room temperature into approximately spherical or rotation-symmetrical bodies or the approximately spherical or rotation symmetrical bodies are injection-moulded onto a wire; c) the bodies are heated to a temperature at which the polymerisation initiator decomposes.

1 . A local system for the release of active principle which consists of approximately spherical or rotation symmetrical bodies which are composed essentially of polymethyl methacrylate or polymethyl methacrylate co-methyl acrylate, zirconium dioxide or barium sulphate and one or more pharmaceutical active principles, and which are produced by radical polymerisation, wherein radical polymerisation activators effective in the temperature range of 10-80° C. or residues of these polymerisation activators selected from the group consisting of aromatic amines, heavy metal salts and barbiturates are not contained therein. 
   
   
       2 . Local system for the release of active principle according to  claim 1 , wherein N,N-dimethyl aniline, N,N-dimethyl-p-toluidine, N,N,-bis-hydroxyethyl-p-toluidine or their consequential products formed during the initiation of radical polymerisation are not contained therein. 
   
   
       3 . Process for the production of the local system of  claim 1  which comprises
 a) producing a paste by mixing methyl methacrylate, polymethyl methacrylate or polymethyl methacrylate co-methyl acrylate, zirconium dioxide and/or barium sulphate, one or more pharmaceutical active principles and a thermally decomposing radical initiator, the paste having a viscosity sufficient to prevent deformation at room temperature by the effect of gravity;   b) injection moulding the paste by an injection moulding device without heating at room temperature into approximately spherical or rotationally symmetrical bodies or injection moulding approximately spherical or rotation symmetrical bodies onto a wire;   c) heating the bodies to a temperature at which the polymerisation initiator decomposes.   
   
   
       4 . Process according to  claim 3 , wherein in step c) heating is by the effect of infrared radiation or by the effect of air or by the effect of microwaves. 
   
   
       5 . Process according to  claim 3 , wherein the decomposing radical initiator is one or more of the substances selected from the group consisting of dibenzoyl peroxide, dilauroyl peroxide and azoisobutyrodinitrile. 
   
   
       6 . Process according to  claim 3 , wherein in step b) a wire is used which is preheated to a temperature in the region of the decomposition temperature of the thermal initiator. 
   
   
       7 . Process according to  claim 3 , wherein the injection moulding tool is made of Teflon or another inert plastic. 
   
   
       8 . The local system of  claim 1 , wherein said active principles are antibiotics.