Lignin–Hydroxypropyl-β-Cyclodextrin Matrix for Chlorzoxazone Loading and Release: Physicochemical, Antioxidant, and Antimicrobial Characterization

Chlorzoxazone (CLZ) is a poorly water-soluble drug whose formulation may benefit from carrier systems capable of drug incorporation and controlled release. This study investigated an epichlorohydrin (ECH)-mediated lignin–hydroxypropyl-β-cyclodextrin (LIG/HP-β-CD) matrix for CLZ loading and release and evaluated its physicochemical, antioxidant, and antimicrobial characteristics. The resulting material was characterized by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG/DTG), while CLZ release was evaluated using kinetic models. The experimentally determined CLZ loading was 41.8 mg/g, corresponding to a loading efficiency of 20.9% relative to the initially added drug. After 180 min, the cumulative amount released reached 29.81 mg/g, corresponding to 71.32% of the loaded CLZ. The release profile was adequately described by the Weibull model (R2 = 0.99394), which provided a useful empirical description of the observed release behavior. FTIR analysis showed changes in the relative contributions of oxygen-containing functional-group regions after modification, while TG/DTG demonstrated an altered thermal profile of the CLZ-loaded material compared with the individual components; these findings were interpreted as supportive rather than definitive evidence of drug–matrix interactions. DPPH radical-scavenging activity was 41.82 ± 1.07% for LIG and 50.32 ± 1.05% for LCD–CLZ; however, because the samples were tested at different concentrations, these values were not interpreted as demonstrating an intrinsic enhancement of antioxidant potency. Under the agar-diffusion conditions, LCD–CLZ produced measurable inhibition against Staphylococcus aureus, Escherichia coli, and Candida albicans, whereas no effective inhibition was observed against Pseudomonas aeruginosa. Overall, the results support further investigation of the LIG/HP-β-CD matrix as a potential platform for CLZ loading and release, while additional structural, biocompatibility, and formulation-specific studies are required before pharmaceutical application can be established.