Sodium Alginate/Sodium Lignosulfonate Composite Gel Beads for Controlled Release of (+)-Pinoresinol: Synthesis, Characterization, and Applications

(+)-Pinoresinol (PIN), a bioactive lignan with antifungal, anti-inflammatory, and chemo-preventive properties, faces pharmaceutical challenges due to poor aqueous solubility, instability, and irritancy. To address these limitations, we engineered sodium alginate (SA)/sodium lignosulfonate (LS) composite gel beads (SA/LS@PIN) as a multifunctional drug carrier. The beads were fabricated through Ca²⁺-mediated cross-linking, where LS integration enhanced structural stability and drug-loading capacity by modulating the gel matrix architecture. Systematic characterization revealed that LS incorporation (1–3% w/v) optimized bead morphology and improved drug entrapment efficiency (0.85% vs. 0.53% for SA-only beads). Under simulated gastrointestinal conditions, SA/LS@PIN exhibited pH-triggered release kinetics: LS delayed PIN release in gastric fluid while promoting intestinal-specific delivery via Ca²⁺-dissociation mechanisms. The composite demonstrated dual functionality, combining controlled release with antioxidant activity (26.64% DPPH radical scavenging attributed to LS-derived sulfonate and hydroxyl groups) and high biocompatibility (>80% cell viability at 3% LS). This sustainable platform integrates pH-responsive drug delivery, oxidative stress mitigation, and low cytotoxicity, offering a promising strategy for biomedical and nutraceutical applications.