OBJECTIVE  To prepare paeoniflorin/O-butyryl chitosan nanoparticles and investigate their in vitro transdermal properties.

METHODS  Optimization of the formulation of paeoniflorin/O-butyryl chitosan nanoparticles was conducted using the Box-Behnken experimental design. Scanning electron microscopy was employed to observe the morphological characteristics of paeoniflorin/O-butyryl chitosan nanoparticles, while laser diffraction particle sizing and Zeta potential analysis were employed to determine their particle size distribution and Zeta potential. The release profile of the nanoparticles was determined using HPLC, and the in vitro release kinetics were investigated. The in vitro transdermal performance of paeoniflorin/O-butyryl chitosan nanoparticles was studied using an improved Franz diffusion cell method and compared with paeoniflorin solution.

RESULTS  Paeoniflorin/O-butyryl chitosan nanoparticles were found to be spherical with a particle size of (131.3±11.8)nm and a Zeta potential of (40.5±2.9)mV. The release mechanism of paeoniflorin/O-butyryl chitosan nanoparticles in vitro followed a zero-order release model. The steady-state permeation flux of paeoniflorin/O-butyryl chitosan nanoparticles and paeoniflorin solution were 15.03 and 9.83 μg·cm⁻²·h⁻¹, respectively. The permeation coefficients were 15.22×10⁻³ and 9.70×10⁻³ cm·h⁻¹, and the skin retention amounts at 8 h were 215.40 and 29.34 μg·cm⁻², respectively.

CONCLUSION  Paeoniflorin/O-butyryl chitosan nanoparticles exhibites a uniform particle size distribution and positively charged surface. Paeoniflorin/O-butyryl chitosan nanoparticles enhances the in vitro skin permeation and retention of paeoniflorin, indicating their potential as a delivery vehicle for paeoniflorin in skin administration.