Development, Optimization, Characterization and Evaluation of Ibrutinib-Loaded Chitosan-Shelled Nanobubbles for Ultrasound-Responsive Targeted Drug Delivery

Abstract

The present study focused on the development of nanosized Ibrutinib-loaded nanobubbles using a chitosan-based shell system. A 3³ Box–Behnken Design (BBD) was employed to investigate the influence of three formulation variables, namely L-α-phosphatidylcholine (A), chitosan concentration (B), and palmitic acid concentration (C), on the particle size and polydispersity index (PDI) of the prepared nanobubbles. A total of 17 experimental runs were generated randomly using Design Expert® software, and the obtained data were evaluated through multiple regression analysis. Numerical optimization was applied to identify the optimum formulation by setting suitable constraints for the response variables. Three optimized formulations (B1–B3) were selected and further characterized. Morphological analysis confirmed the formation of well-defined core–shell nanobubbles with particle sizes ranging between 150 and 200 nm. The optimized nanobubbles demonstrated an encapsulation efficiency of 82.58% and a drug loading capacity of 17% for Ibrutinib. In vitro drug release studies showed that the optimized nanobubble formulation released 93.52% of Ibrutinib within 24 hours, which was considerably higher than the release observed from the conventional Ibrutinib suspension. Cellular uptake studies using HepG2 cells revealed enhanced fluorescence, with a mean fluorescence intensity of 6.12, approximately 1.5-fold greater than that obtained with Ibrutinib-loaded nanobubbles in the absence of ultrasound exposure. Furthermore, in vitro cytotoxicity results indicated that ultrasound-assisted nanobubbles promoted efficient intracellular drug release and improved therapeutic sensitivity. Overall, the findings suggest that chitosan-shelled Ibrutinib nanobubbles represent a promising platform for contrast-enhanced tumor imaging as well as targeted therapeutic drug delivery.