Intra-arterial Controlled Release from Hollow Cylindrical Implants

J.C.D. IBARRA; I.M. HELBLING; J.A. LUNA

Suzhou

Simposio; 4th Annual Symposium of Drug Delivery Systems (SDDS); 2014

BIT Life Sciences

New implants for controlled release of oncological drugs to minimize side effects of chemotherapy and to achieve localized release near tumors were investigated. A site-specific delivery system using matrices of ethylene vinyl acetate copolymer (EVA) loaded with paclitaxel for intraarterial implantation was designed. The hollow cylindrical polymeric matrices were fabricated by a hot-melt extrusion procedure. Characterization of controlled release system was carried out to determine the initial drug content, paclitaxel diffusion coefficient in the matrix and paclitaxel solubility in EVA and in release medium. The in vitro release of paclitaxel from EVA  matrices were conducted using two release medium: ultra filtered water with an ethanol content of 20% V/V and PBS + SDS 0.3% w/V. Results showed that release follows typical matrix-type release kinetic. At day 15, more than 85 % of initial content was released. In addition, hollow cylindrical matrices were placed inside pig heart arteries and in vitro release test were conducted as before. Besides, permeation studies were performed to determine paclitaxel diffusion coefficient in the pig artery. Results showed a lag time in release profiles. Lag time duration was directly related to the thickness of the arterial wall. However, arterial wall do not control paclitaxel delivery. It acts as a non-controlling release barrier. This could be due mainly to the higher paclitaxel diffusion coefficient in the artery compared with that in the matrix. Results obtained in the present contribution show a potential use of EVA-paclitaxel matrix systems for endovascular treatment.