Synthesis and characterization of hydroxyethyl chitosan as a functional pharmaceutical excipient

This study aims to develop an excellent pharmaceutical excipient based on crosslinked hydroxyethyl chitosan (G-HECTS(GA)), designed to exhibit high intrinsic viscosity and superior moisture absorption and retention properties for wound healing applications. Hydroxyethyl chitosan (HECTS) was synthesized from chitosan through a derivatization reaction with bromoethanol under alkaline conditions, achieving a maximum solubility of 6.8 ± 0.2 g/100 g water. The HECTS was further crosslinked with glutaraldehyde (GA) to produce G-HECTS(GA). Structural characterization of the product was performed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Key parameters, including crosslinker dosage, reaction time, temperature, and stirring speed, were optimized to evaluate their effects on intrinsic viscosity. The physicochemical properties and wound healing efficacy of G-HECTS(GA) were systematically assessed in a rat wound model. Under optimal conditions (35 °C, 25 μL GA, 18 h reaction time), the crosslinked product demonstrated an intrinsic viscosity of 1870 ± 70 mL/g, a moisture retention rate of 39 % ± 3 %, and a moisture absorption rate of 39.1 % ± 0.7 %. G-HECTS(GA) rapidly formed a stable film on wound surfaces, effectively absorbing exudates and promoting wound healing. The material exhibited excellent stability, biocompatibility, and antibacterial activity, along with significant anti-inflammatory effects. These properties highlight the potential of G-HECTS(GA) as a high-performance pharmaceutical excipient for hemostatic spray formulations, offering a promising solution for mucosal wound repair and related biomedical applications.