Drug delivery in pluronic micelles: effect of high-frequency ultrasound on drug release from micelles and intracellular uptake

The effect of high-frequency ultrasound oil doxorubicin (DOX) release from Pluronic micelles and intracellular DOX uptake was studied for promyelocytic leukemia HL-60 cells, ovarian carcinoma drug-sensitive and multidrug-resistant (MDR) cells (A2780 and A2780/ADR, respectively), and breast cancer MCF-7 cells. Cavitation events initiated by high-frequency ultrasound were recorded by radical trapping. The onset of transient cavitation and DOX release from micelles were observed at much higher power densities than at low-frequency ultrasound (20-100 kHz), Even a short (15-30 s) exposure to high-frequency ultrasound significantly enhanced the intracellular DOX uptake from PBS, RPMI 1640, and Pluronic micelles. The mechanism,, of the observed effects are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.