Chitosan-functionalized antelope horn particles as Pickering stabilizers: enhancement of thermal stabilization and in vitro release of volatile oil from Acorus tatarinowii Schott

Abstract

Acorus tatarinowii Schott volatile oil (ATVO) exhibits significant pharmacological activity but undergoes oxidative decomposition under thermal conditions, reducing active component content and formulation stability. This study introduced Pickering emulsion technology to enhance the antioxidant capacity of ATVO and the stability of solid preparations. Antelope horn (AH) powder, derived from Lingzhu Powder, is pharmacologically active and physically stable; however, it is highly hydrophilic and thus unsuitable as a stabilizer. Through chitosan modification, the contact angle of AH was increased from 62.8° to 87.3°, enabling it to function as an effective Pickering stabilizer. A high-speed shear emulsification method was used to construct Pickering emulsions stabilized by modified AH. Under thermal stress at 60 °C, the Pickering emulsion group showed significantly lower peroxide value and malondialdehyde content compared to free ATVO. GC–MS analysis confirmed a superior stability of volatile components in the emulsion. In vitro dissolution tests in artificial gastric/intestinal fluids demonstrated that the emulsion released ATVO faster and more sustainably over 48 h. In artificial intestinal fluid, the cumulative release ratios of α-asarone and β-asarone reached 66.25 % and 91.32 %, respectively, which were 1.43 and 1.26 times those of ATVO group. This is attributed to the interfacial barrier effect of chitosan-modified AH particles. Chitosan surface modification effectively regulates the interfacial properties of AH, and the resulting Pickering emulsion enhances the thermal stability and dissolution rate of ATVO.