Pickering Emulsion Stabilized by Chitosan-Modified Saigae Tataricae Cornu Particles for Improving the Oxidative Stability and In Vivo Pharmacokinetics of Acorus tatarinowii Schott Volatile Oil.

Background/Objectives: Acorus tatarinowii Schott volatile oil (ATVO), a bioactive component of traditional Chinese medicine, is susceptible to light-induced oxidation and compositional changes. This study aimed to develop a chitosan-modified Saigae Tataricae Cornu particle (MSTC)-stabilized Pickering emulsion (PE) to improve the light-oxidative stability and in vivo disposition of ATVO. Methods: Saigae Tataricae Cornu particles were modified with chitosan and used to prepare an oil-in-water PE encapsulating ATVO. Particle wettability, morphology, structural interactions, emulsion type, interfacial distribution, droplet size, and zeta potential were characterized. The light-oxidative stability of ATVO was evaluated under light using peroxide value, malondialdehyde content, and gas chromatography-mass spectrometry (GC-MS) analysis. The pharmacokinetic behavior of α-asarone and β-asarone was further investigated in rats. Results: Chitosan modification increased the contact angle of Saigae Tataricae Cornu particles from 65.37° to 83.23°, indicating improved wettability and interfacial affinity. The resulting PE showed good physical stability, with a droplet size of 2.51 μm and a zeta potential of +32.00 mV. Confocal laser scanning microscopy (CLSM) confirmed that MSTC particles adsorbed at the oil-water interface and encapsulated ATVO within the oil droplets. Compared with free ATVO and the physical mixture, the PE reduced peroxide and malondialdehyde formation, slowed light-induced changes in volatile components, and better preserved major bioactive constituents. Pharmacokinetic analysis showed that the plasma concentration-time curve from 0 to t (AUC0-t) and maximum plasma concentration (Cmax) of α-asarone increased by 2.02- and 2.47-fold, respectively, whereas the effect on β-asarone was relatively limited. Conclusions: MSTC-stabilized PE provides an effective interfacial-barrier strategy for protecting ATVO against light-oxidative deterioration. This study highlights the potential of modified natural medicinal particles as green stabilizers for improving the stability, quality consistency, and delivery performance of volatile-oil-containing traditional Chinese medicine preparations.