A study of the formulation design of acoustically active lipospheres as carriers for drug delivery

Acoustically active lipospheres (AALs) were prepared using perfluorocarbons and coconut oil as the cores of inner phase. These AALs were stabilized using coconut oil and phospholipid coatings. A lipophilic antioxidant, resveratrol, was the model drug loaded into the AALs. AALs with various percentages of perfluorocarbons and oil were prepared to examine their physicochemical and drug release properties. Co-emulsifiers such as Brij 98 and Pluronic F68 (PF68) were also incorporated into AALs for evaluation. AALs with high resveratrol encapsulation rates (∼90%) were prepared, with a mean droplet size of 250-350 nm. The AALs produced with perfluorohexane as the core material had larger particle sizes than those with perfluoropentane. Resveratrol in these systems exhibited retarded drug release in both the presence and absence of plasma in vitro; the formulations with high oil and perfluorocarbon percentages showed the lowest drug release rates. The addition of PF68 slightly but significantly reduced resveratrol delivery from the AALs. Ultrasound treatment of 1 MHz produced an increase in the drug release from the systems, illustrating the drug-targeting effect of the combination of AALs and ultrasound.