Dual drug encapsulated LAM-anchored liposomes for enhanced macrophage association and intracellular antimycobacterial drug delivery

Objective Tuberculosis (TB) remains difficult to treat because Mycobacterium tuberculosis persists within macrophages, limiting intracellular drug exposure. This study aimed to develop and evaluate a lipoarabinomannan (LAM)-functionalized liposomal nanocarrier for enhanced macrophage uptake and simultaneous delivery of rifampicin (RIF) and isoniazid (INH). Methods LAM-functionalized liposomes were prepared by thin-film hydration, with hydrophobic RIF incorporated into the lipid bilayer and hydrophilic INH encapsulated within the aqueous core. Liposomes were characterized by transmission electron microscopy, dynamic light scattering, zeta-potential analysis, and fluorescence microscopy. Drug release was evaluated at pH 7.4 and 6.0. Macrophage uptake was assessed in THP-1-derived macrophages using fluorescent proxy liposomes, while antimycobacterial activity was evaluated against Mycobacterium smegmatis and in M. smegmatis -infected macrophages. Results LAM conjugation increased the hydrodynamic diameter of the liposomes from approximately 240–750 nm, with a polydispersity index of 0.196. LAM-functionalized liposomes showed approximately 2-fold and 3-fold increases in intracellular curcumin and rhodamine fluorescence, respectively, compared with non-functionalized liposomes. Both drugs exhibited sustained release over 72 h, with greater cumulative release at pH 6.0 than pH 7.4. Dual-drug liposomes demonstrated greater antimycobacterial activity than single-drug formulations. In infected macrophages, LAM-functionalized dual-drug liposomes reduced bacterial burden from approximately 2.3–2.4 × 10⁶ to 1.3–1.4 × 10⁶ CFU/ml ( p = 0.002, n = 4), whereas non-LAM liposomes produced no significant reduction. The formulation remained physically stable during 10 days of storage at 4°C. Conclusion LAM-functionalized dual-drug liposomes enhanced macrophage uptake and intracellular antimycobacterial activity in vitro, providing proof of concept for macrophage-associated delivery of RIF and INH. Further validation in slow-growing pathogenic mycobacteria and in vivo models is required to establish therapeutic potential.