Docetaxel Oral Delivery System Using Natural Nanoparticles Derived from Ganoderma: Enhanced Pharmacokinetics, Potent Cytotoxicity, and Macrophage-Activating Properties

Background/Objectives: Natural macromolecule-based drug delivery carriers have gained extensive attention for biomedical applications. This study aimed to construct an efficient oral delivery system for the widely used antitumor drug docetaxel (DTX) by utilizing natural nanoparticles derived from Ganoderma (LZ-Nnps). Methods: LZ-Nnps loaded with DTX (LZ-Nnps-DTX) were fabricated via an optimized heat-induced self-assembly approach and characterized for morphology, particle size, zeta potential, stability, drug loading, encapsulation efficiency, and molecular interactions with DTX. Intestinal absorption, pharmacokinetics, and tissue distribution were respectively assessed, while antitumor efficacy, macrophage internalization mechanisms, and immunomodulatory activation were further investigated. Results: The optimized formulation showed a particle size of 361.3 ± 5.3 nm, zeta potential of −39.55 ± 1.31 mV, drug loading of 1.51 ± 0.08%, and near-complete encapsulation efficiency (99.97 ± 0.02%), with favorable stability in gastrointestinal fluids. Hydrogen bonding and hydrophobic interactions effectively kept DTX in a stable amorphous state. LZ-Nnps-DTX markedly improved DTX aqueous solubility, dissolution, and intestinal absorption. In vivo assays showed oral LZ-Nnps-DTX achieved 34-fold higher Cmax and 7.8-fold larger plasma AUC0-t than free DTX, and mainly accumulated in the liver and lung. The nanoparticles entered Caco-2 cells via macropinocytosis and mainly accumulated in the liver. LZ-Nnps-DTX exerted strong cytotoxicity against HepG2, A549, and HCT116 cells, was internalized by RAW264.7 macrophages through caveolae-mediated endocytosis and phagocytosis, and stimulated TNF-α and NO production to suppress tumor growth. Conclusions: These findings demonstrate that LZ-Nnps-DTX effectively enhances oral bioavailability, exerts potent antitumor effects, and activates macrophage-mediated immunity, supporting its promise as an oral DTX delivery system.