DEVELOPMENT OF A NOVEL HYDROPHOBIC POLYMERIC MATRIX FOR STEROIDAL DRUG RELEASE: IN VITRO AND IN VIVO STUDIES

V. HEREDIA, I. D. BIANCO, G. CUESTA, H. TRÍBULO, S. FAUDONE , S. CUFFINI, R. ALASINO AND D. M. BELTRAMO

Los Cocos, Córdoba, Argentina

Simposio; III Argentine-Chilean Polymer Symposium.; 2005

ARCHIPOL 05

Silicone, hydrophobic elastomers are one of the commonest biomaterials presently used in controlled delivery systems of steroid molecules, with aim of controlling estrus cycle in livestock. Commercially available intravaginal devices have a silicone rubber skin with an homogeneous dispersion of 1-2 g micronized progesterone (P4). The most common silicone elastomer is polydimethyl siloxane (PDMS). Thermosets rubbers, like PDMS, are three-dimensional molecular networks, with long molecules held together by chemicals bonds.  Other hydrophobic elastomers, polyisoprene (PI), are also thermosets rubbers. PI contain carbon-carbon backbones, unlike PDMS, which have flexible siloxane backbones. Here we report an in vitro and in vivo kinetics study on progesterone release from a polymeric matrix of PI in comparison with PDMS. The goal of this PI matrix is to improve the P4 release in vitro and in vivo better than PDMS matrices. The P4 release rate is regulated to the matrices area and the crystalline drug form. This results made possible to reduce the inicial drug loaded within the intravaginal device. In vivo studies show that critical plasma levels of progesterone (2ng/ml) were reached with the commercial silicone device (CIDR) and PI devices,  containing 1.9 g progesterone and  0.5g. progesterone respectively.