In the field of pharmaceutical industry, the controlled-release drugs have received considerable attention in the last years. Impregnation using supercritical fluid technology has already proven its feasibility in the preparation of controlled release systems. The use of supercritical fluids such as supercritical CO2 has provided a ‘clean’ and effective alternative to traditional methods of drug releasing and polymer processes. In particular, scCO2 has a number of unique properties that make it possible to process both bioactive molecules and amorphous polymers without using toxic organic solvents or elevated temperatures. A high purity product, free of residual solvents is obtained, since no organic solvents are involved in the impregnation process. Here, we review the advantages of supercritical fluid and the preparation of controlled-release drugs by supercritical solvent impregnation.