Fabricating cauliflower-like and dumbbell-like Janus particles: Loading and simultaneous release of DOX and ibuprofen.

Most recent studies on Janus particles have concentrated on amphiphilic Janus particles. Herein, a facile and efficient method based on polymerization-induced phase separation is presented to fabricate Janus particles with different morphologies. Theses novel hydrophilic Janus particles with two distinct hydrophilic domains have been prepared by combination of distillation precipitation polymerization (DPP) and seeded emulsion polymerization. Crosslinked poly(2-hydroxyehtyl methacrylate) (PHEMA) cores were synthesized via DPP and used as seed particles. Also, methacrylic acid (MAA) was used as second hydrophilic monomer. Effect of feeding approach, and reaction medium were investigated on the morphology of fabricated composite particles. Different morphologies such as cauliflower-like, dumbbell-like, and core-shell toward cauliflower-like structures were obtained by varying feeding approach and polymerization medium. The morphology of resultant particles was observed by means of FE-SEM and TEM images and their particle sizes were confirmed by DLS. Fabricated composite particles were used to simultaneously carry both DOX and ibuprofen. Drug release studies showed that Janus particles can be used in loading and release of two drugs simultaneously. However, release behaviors of DOX and ibuprofen were different at different pH values. Also, release behavior was significantly affected by the structure of composite particles.