Physicochemical and in vitro characterisation of antifungal PVA/chitosan composite wet-spun fibres loaded with hydroxypropyl-γ-cyclodextrin/amphotericin B complexes.

Abstract

Chronic wounds infected by Candida albicans impose a significant clinical burden, yet topical amphotericin B (AMB) delivery is constrained by low aqueous solubility. Wet-spun poly(vinyl alcohol) (PVA)/chitosan fibres loaded with an AMB/hydroxypropyl-γ-cyclodextrin (HP-γ-CD) inclusion complex were developed as a sustained-release antifungal wound dressing. Phase solubility analysis confirmed inclusion complex formation with an apparent stability constant of 36.1 × 103 M⁻1 in distilled water (AL-type profile, R2 = 0.9984), characterised by Fourier-transform infrared spectroscopy (FTIR), 1H NMR, and scanning electron microscopy (SEM). IC-SE-1 achieved ∼ 354-fold and ∼ 136-fold solubility enhancement in distilled water and phosphate-buffered saline (PBS, pH 7.4), respectively, while fully retaining antifungal activity (MIC = 1 µg/mL; p = 0.112 vs. pure AMB). The complex was incorporated into fibres at four PVA:chitosan ratios and crosslinked with tripolyphosphate and glutaraldehyde. Formulation P6C4 (PVA 60%:chitosan 40%) demonstrated the most favourable overall performance, with the highest water-holding capacity (346.51 ± 4.10%), swelling (463.40 ± 11.12%), tensile strength (18.47 ± 2.18 MPa), and elongation (431.57 ± 52.22%). Woven fibres maintained inhibition zones against C. albicans from day 2 to day 7, with AMB release exceeding the MIC throughout, while haemolysis remained below 5% (ASTM F756-08). HP-γ-CD complexation enables sustained above-MIC AMB delivery from a dual-crosslinked biopolymeric dressing, providing in vitro proof-of-concept for Candida-infected chronic wounds, pending cytotoxicity and in vivo validation.