STUDIES ON NATURAL GUM-BASED INJECTABLE HYDROGEL FOR WOUND HEALING APPLICATIONS

Abstract

This thesis describes the fabrication and characterization of novel injectable hydrogels using functionalized natural gums (Moringa oleifera gum, mesquite gum, neem gum, and okra gum) with multi-aldehyde groups and carboxymethyl chitosan crosslinked through a Schiff base mechanism at 37°C. The optimal concentration of an oxidizing agent is determined to maximize aldehyde content in each gum, which in turn affects the gelation time and physical properties such as syringeability, porosity, self-healing ability, and gel content. Structural characterization is performed using Fourier-transform infrared and nuclear magnetic resonance spectroscopy, while surface morphology and rheological properties are analyzed by scanning electron microscopy and rheometry, respectively. The swelling ratio was assessed for dry and gel form in phosphate buffer saline at pH 5.5, 7.4, and 8.5 at 37°C, indicating pH-responsive behavior. Ciprofloxacin HCl is loaded as a model drug, and its release behavior is studied under different pH conditions (5.5, 7.4, and 8.5) for dry and gel form, revealing a pH-dependent release profile. The Korsemeyer– Peppas model evaluates drug release mechanisms. In vitro cytotoxicity using L-929 fibroblast cells confirms the biocompatibility of the injectable hydrogels, with varied cell viability depending upon the gum used. Hemolysis assays are also carried out to ensure the biocompatibility of the injectable hydrogels. Additionally, antibacterial activity is assessed against Gram-positive and Gram-negative bacteria, and hydrolytic degradation of the injectable hydrogels is evaluated in PBS at pH 7.4.