A ternary synergistic composite sponge fabricated from silk fibroin, sodium alginate, and chitosan: A robust method for efficient enrichment of diclofenac sodium against complex biological interference

A ternary SF-SA-CS biomass sponge (SSC) was fabricated via electrostatic and hydrogen bonding. • SSC exhibits high adsorption capacity and selectivity for DCF-Na. • Mechanism studies confirm enrichment driven by hydrogen bonding and electrostatic forces. • SSC-HPLC method enables sensitive monitoring of DCF-Na pharmacokinetics in mouse plasma. • SSC-HPLC method provides a robust tool for future in vivo pharmacodynamics of drugs. Diclofenac sodium (DCF-Na) is a widely used non-steroidal anti-inflammatory drug. However, monitoring its dynamic behavior in vivo remains challenging due to the complexity of biological matrices. Herein, a novel biomass sponge adsorbent (SSC) was successfully fabricated via the composite of silk fibroin (SF), sodium alginate (SA), and chitosan (CS) through electrostatic and hydrogen bonding interactions. The resulting SSC exhibited a uniform three-dimensional porous architecture with a specific surface area of 8.64 m 2 ·g −1 and a mesoporous structure (average pore size 17.0 nm). Benefiting from the synergistic effect of abundant amino, carboxyl, and hydroxyl groups, SSC achieved rapid adsorption equilibrium within 60 min and a high saturated adsorption capacity of 165.8 mg·g −1 . Kinetic and isothermal studies revealed that chemisorption and monolayer adsorption were the dominant mechanisms. Significantly, SSC demonstrated remarkable selectivity toward DCF-Na and excellent anti-interference capability in complex coexisting systems, as confirmed by comparative adsorption experiments and cluster analysis. Mechanistic investigations combining spectroscopic analysis and molecular simulations verified that the adsorption was primarily driven by hydrogen bonding and electrostatic interactions. Furthermore, an SSC-HPLC method was developed for the determination of DCF-Na in plasma, yielding a wide linear range, high precision ( RSD  < 0.793%), and satisfactory accuracy (recovery: 102%–108%). The established method was successfully applied to monitor the plasma drug concentration of DCF-Na in mice via high-performance liquid chromatography. This work presents an efficient, stable, and environmentally friendly sample pretreatment strategy based on a biomass adsorbent for monitoring of drug concentrations in biological matrices. Download: Download high-res image (172KB) Download: Download full-size image