Synthesis and characterization of two novel amphotericin B-chitosan nanoparticles cross-linked with glutaraldehyde and phthaldialdehyde for the treatment of invasive candidiasis.

Amphotericin B (AmB) is a potent broad-spectrum antifungal agent widely used to treat invasive candidiasis (IC); however, its clinical application is limited by severe toxicity, particularly nephrotoxicity. In this study, chitosan (CS)-AmB nanoparticles (NPs) cross-linked with glutaraldehyde (Glu) and phthaldialdehyde (Ph) were developed to enhance therapeutic efficacy and reduce AmB toxicity. CS-Glu-AmB and CS-Ph-AmB NPs were synthesized by cross-linking CS with Glu or Ph, followed by AmB incorporation. NP formation was confirmed by FT-IR, 1H NMR, and XRD analyses. The average particle sizes of CS-Glu-AmB and CS-Ph-AmB NPs were 64.00 ± 3.71 nm and 82.00 ± 5.38 nm, with zeta potentials of +29.00 ± 4.12 mV and + 55.00 ± 7.01 mV, respectively. Drug loading was 5.63 ± 2.01 % and 4.91 ± 1.83 %, and encapsulation efficiency reached 94.66 ± 2.55 % and 81.74 ± 3.01 % for CS-Glu-AmB and CS-Ph-AmB, respectively. After 12 h, hemolysis was significantly lower for CS-Glu-AmB (15.75 ± 0.96 %) and CS-Ph-AmB (16.41 ± 0.21 %) compared with plain AmB (79.62 ± 0.51 %) and Fungizone® (67.41 ± 16.80 %). HEK-293 cell viability after 72 h was significantly higher for CS-Glu-AmB (57.63 ± 2.14 %) and CS-Ph-AmB (53.96 ± 3.76 %) than for plain AmB (24.27 ± 1.32 %) and Fungizone® (35.81 ± 3.55 %). CS-Glu-AmB and CS-Ph-AmB NPs inhibited Candida albicans biofilm formation (85.61 ± 3.42 % and 83.39 ± 4.46 %, respectively) and effectively cured IC in BALB/c mice. These findings indicate that CS-Glu-AmB and CS-Ph-AmB NPs are promising candidates for IC treatment due to their enhanced safety and reduced cytotoxicity compared to conventional AmB formulations.