Curcumin‐loaded polycaprolactone nanoparticles prepared by emulsion evaporation stabilized with a <scp>pH</scp> ‐responsive emulsifier

Abstract This study focuses on encapsulating curcumin (CUR) with low water solubility in polycaprolactone (PCL) particles using the emulsion evaporation method. In order to obtain particles with desired properties, a pH‐sensitive emulsifier is synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The properties of particles obtained from commercial (Pluronic P105) and synthetic emulsifiers, ABP‐1 and ABP‐2 (with different HLB values), were evaluated. The morphology of the final particles formed by ABP‐1 is spherical and more uniform. The molecular structure design of ABP‐1 enabled the production of particles with a narrow size distribution, a feat not achievable with Pluronic P105. The optimal sample prepared from ABP‐1, with an entrapment effectiveness (EE%) of 78.4% and an average particle size of 258 ± 12 nm, was able to deliver CUR in a controlled manner. Also, zeta potential values show that ABP‐1 is well separated from the drug‐carrying particles in the washing phase, and the particles without emulsifier were evaluated to investigate the drug release. Among other models, the Weibull model showed the best agreement with the experimental data, and based on β parameter value of 0.46, it can be concluded that the drug release mechanism is Fickian. The particles synthesized using both methods give outstanding antibacterial activity (99.9%). Highlights Synthesis of a pH‐responsive block copolymers by reversible addition fragmentation chain transfer (RAFT) polymerization. Application of the block copolymers as smart emulsifier. Preparation of polycaprolactone (PCL) nanoparticles containing curcumin by evaporation emulsion method. The dominance of Fickian diffusion in drug release. Excellent antibacterial properties over a period of time.