Drug delivery system
The subject invention provides a drug delivery system comprising at least one compartment consisting of (i) a drug-loaded thermoplastic polymer core, (ii) a drug-loaded thermoplastic polymer intermediate layer and (iii) a non-medicated thermoplastic polymer skin covering the intermediate layer, wherein said intermediate layer is loaded with (a) crystals of a first pharmaceutically active compound and with (b) a second pharmaceutically active compound in dissolved form and wherein said core is loaded with said second compound in dissolved form.
1. A drug delivery system comprising (i) a drug-loaded thermoplastic polymer core, (ii) a drug-loaded thermoplastic polymer intermediate layer and (iii) a non-medicated thermoplastic polymer skin covering the intermediate layer, wherein said intermediate layer is loaded with (a) crystals of a first steroid and with (b) a second steroid in dissolved form and wherein said core is loaded with said second steroid such that steroid in the core is present only in dissolved form.
2. A drug delivery system according to claim 1 , wherein the delivery system has a substantially ring-shaped form and is intended for vaginal administration.
3. A drug delivery system according to claim 1 , wherein at least the skin but optionally also the core and the intermediate layer comprise ethylene-vinylacetate copolymer as the thermoplastic polymer.
4. A drug delivery system according to claim 3 , wherein the core and the intermediate layer comprise the same grade of ethylene-vinylacetate copolymer as the thermoplastic polymer.
5. A drug delivery system according to claim 3 , wherein the core and the intermediate layer comprise a different grade of ethylene-vinylacetate copolymer as the thermoplastic polymer.
6. A method of manufacturing the three-layered drug delivery system of claim 1 comprising:
(i) producing a loaded homogenous polymer core granulate and a loaded homogenous polymer intermediate layer granulate;
(ii) co-extruding the core granulate and the intermediate layer granulate with a polymer skin granulate to form the three-layered drug delivery system.
7. A method according to claim 6 wherein step (i) comprises:
(a) grinding the polymer;
(b) dry powder mixing the ground polymer with the active compounds to be loaded in the intermediate layer;
(c) dry powder mixing the ground polymer with the active compound to be loaded in the core;
(d) blend extruding the resulting powder mixtures of steps (b) and (c);
(e) cutting the resulting loaded polymer strands into granules, thereby obtaining a core granulate and an intermediate layer granulate;
(f) lubricating both core granulate and intermediate granulate with a lubricant;
wherein steps (b) and (c) are interexchangeable.