Determining the Optimal Conditions for the Production by Supercritical CO of Biodegradable PLGA Foams for the Controlled Release of Rutin as a Medical Treatment.

Poly(D,L,-lactide--glycolide) (PLGA) foam samples impregnated with rutin were successfully produced by supercritical foaming processes. A number of parameters such as pressure (80-200 bar), temperature (35-55 °C), depressurization rate (5-100 bar/min), ratio lactide:glycolide of the poly(D,L,-lactide--glycolide) (50:50 and 75:25) were studied to determine their effect on the expansion factor and on the glass transition temperature of the polymer foams and their consequences on the release profile of the rutin entrapped in them. The impregnated foams were characterized by scanning electron microscopy, differential scanning calorimetry, and mercury intrusion porosimetry. A greater impregnation of rutin into the polymer foam pores was observed as pressure was increased. The release of rutin in a phosphate buffer solution was investigated. The controlled release tests confirmed that the modification of certain variables would result in considerable differences in the drug release profiles. Thus, five-day drug release periods were achieved under high pressure and temperature while the depressurization rate remained low.