Phospholipids-based ultrasonic microbubbles for catechins encapsulation and ultrasound-triggered release

Abstract

Objective: The objective of this work was to examine the application of catechins-containing phospholipids-based ultrasonic microbubbles (PUM) in ultrasound-induced delivery. Methods: Catechins-containing PUM were prepared by dissolving lyophilized PUM powder in catechins solution. Morphologic characteristics of catechins-loaded microbubbles were measured compared with blank microbubbles. The contrast enhancement in vivo of loaded microbubbles was measured by contrast-tuned imaging (CnTi) technique. Encapsulation efficiency and ultrasound-stimulated release profile in vitro were detected. Results: Incorporation of catechins in PUM had little effect on the mean particle size and microbubble concentration. Catechins encapsulation efficiency maintained relatively stable with increasing catechins concentration. However, the net amount of catechins encapsulated per milliliter of PUM solution showed a positive relationship with increasing catechins concentration. Effective enhancement in ultrasonic images was observed under CnTi technique combined with catechins-containing PUM. There was no significant difference in the contrast intensity and the longevity of CnTi enhancement between the images of the loaded and unloaded PUM. From ultrasound-stimulated release profile in vitro, 30 s ultrasound stimulated more than 90% of catechins released from loaded PUM. Conclusions: PUM exhibited satisfactory morphologic characteristics, loading ability, and acoustical activity, which could be recommended as a potential carrier for ultrasound-induced delivery.