The Iodine–Dextrin–Lithium Complex: Morphology, Antibacterial Activity, and Cytotoxicity

A new iodine-dextrin-lithium complex (IDLC) was synthesized and structurally characterized as a hybrid supramolecular system combining antiseptic, stabilizing, and biocompatible components. The compound integrates iodine as the primary antimicrobial agent, lithium as a coordination and stabilization element, and dextrin as a biodegradable polysaccharide matrix enabling sustained release. Physicochemical analyses confirmed the formation of a uniform, thermally stable complex. Biological evaluation revealed strong bactericidal activity, with minimum bactericidal concentrations (MBCs) ranging from 1.95 to 15.63 µg mL^-1 against both Gram-positive and Gram-negative pathogens, including multidrug-resistant <i>Staphylococcus aureus</i> and <i>Acinetobacter baumannii</i>. Cytotoxicity studies revealed moderate, concentration-dependent effects on human peripheral blood mononuclear cells (CC₅₀ = 0.23-0.48 mg/mL; 11.7-24.4 μg I/mL) and low toxicity toward MDCK cells (CC₅₀ = 10-20 mg/mL; 507-1014 μg I/mL), confirming a favorable safety profile. IDLC exhibited cytotoxic effects on tumor cell lines (HepG2, HeLa, AGS, K562, and H9) as well as on the normal MeT-5A cell line; however, the CC₅₀ values are similar, and selectivity indices are close to 1, indicating no selective cytotoxicity toward tumor cells. Thus, IDLC demonstrates non-specific cytotoxicity at high concentrations, consistent with its iodine content. The research confirms that iodine can be effectively stabilized within a dextrin-lithium framework to yield a biologically active, thermally resistant complex, suitable for pharmaceutical use.