Production of liposomes loaded alginate aerogels using two supercritical CO2 assisted techniques

Ampicillin loaded liposomes were entrapped in alginate aerogels to create a meta-carrier (a carrier within another carrier), to obtain a prolonged drug release. Liposomes with a diameter of 200 ± 77 nm and with an encapsulation efficiency of 69.5 ± 1.2% were produced using a supercritical assisted formation process (SuperLip). Then, they were entrapped into alginate gels, and the final loaded aerogels were obtained by supercritical CO2 drying. The successful entrapment of liposomes into aerogels was confirmed by EDX analysis. Drug release tests demonstrated that ampicillin release time from these meta-carriers was about 4 days; i.e., about twice than its release time from liposomes alone. Two mass transfer resistances in series operated in the overall drug release: One related to liposomes lipidic layers and one due to the presence of the alginate aerogel matrix.