**6. Conclusions**

Impregnated scaffolds are an interesting alternative to be used in pharmacology and biomedicine because scaffolds act not only as a physical support but also as a carrier of a bioactive substance with a controllable release. The possibility of regulating the rate of the scaffold degradation and the kinetics of drug release make it easy to fabricate particular drug release systems. Bone regeneration, implants, hormonal treatment, and tissue engineering applications are fields where scaffolds could be used. The way to create the porosity in the polymer originated a multiple scaffold fabrication methods based most of them in molding and removing the used organic solvent in a posterior step. Supercritical CO2 has been used as dryer in many conventional methods as sol-gel where the solvent must be evaporated. However, in these methods supercritical CO2 is able to remove almost the totality of used organic solvent, which requires several process steps. Another way to use supercritical CO2 is in the gas foaming process. In this sense the porosity is created at the same time that the bioactive substance is incorporated, avoiding the use of organic solvent. Moreover these processes do not use high temperature, so the activity of the bioactive molecule would hold unaltered. Foaming process changes not only the polymer porosity but also other properties as melting, crystallization or glass transition

temperature, melting heat, and so on and thus could produce more fragile or harder polymer depending on the foaming conditions. Particularly in our facilities, polycaprolactone/quercetin scaffolds were prepared using supercritical CO2 foaming + impregnation one-step process in an efficient way. Release profiles showed that quercetin took five times longer to dissolve the same amount of quercetin into the first 8 h where it was placed into scaffold.
