Supercritical Fluid Impregnation for the Preparation of Controlled Delivery Systems

Controlled drug delivery products, using biocompatible or biodegradable polymers, have received considerable attention in the last years. These substances provide in general a more controlled release rate of assumption of the drug by the body improving its therapeutic action. In fact, there is a growing interest of the pharmaceutical industry in the development of these systems. Impregnation using supercritical fluid technology has already proven its feasibility, in the preparation of controlled release systems. In this technique the drug component is dissolved in a compressed gas (carbon dioxide) that is used as a mobile phase and that, also, swells and stretches the polymer matrix, facilitating the diffusion of the drug, and increasing the rate of impregnation. A high purity product, free of residual solvents is obtained, since no organic solvents are involved in the impregnation process. In this chapter, the development of different successful controlled release systems is presented.