Sprayable Carbopol hydrogel with soluble beta-1,3/1,6-glucan as an active ingredient for wound healing – Development and in-vivo evaluation

Abstract

Chronic wounds represent a significant health problem worldwide. There is a need for advanced- and cost-efficient wound healing products able to increase patient comfort and reduce the healing time. The aim of this study was to develop a sprayable hydrogel dressing with beta-glucan (βG) as the active ingredient, targeting future application in the treatment of both chronic and burn wounds. The βG was chosen as an active ingredient because of its promising wound healing capabilities, whereas Carbopol 971P NF (Carbopol) was chosen as the thickening agent in the formulation due to several attractive characteristics such as its low viscosity, low toxicity, high transparency and good ion tolerance. Four different hydrogel formulations were prepared with varying Carbopol concentrations. The higher Carbopol concentration, 0.5% (w/w), was used to prepare three formulations comprising the HighCP:NoβG, HighCP:LowβG and the HighCP:MediumβG formulation, respectively. Lower Carbopol concentration, 0.25% (w/w), was used to prepare the LowCP:HighβG formulation. The content of βG varied from 0.25% in the HighCP:LowβG, 0.5% in the HighCP:MediumβG and 1.0% (w/w) in the LowCP:HighβG formulation, respectively. The first part of the study focused on the rheological characterization of the hydrogels and the fluid affinity testing. All formulations were confirmed to be stable gels; the βG was shown to augment the gel strength by increasing the yield strength of the gel in a dose dependent manner. The stability of the formulations containing either Carbopol alone or in a combination with βG did not deteriorate over 26 weeks, and the fluid donation and absorption study indicated a fluid donation profile, which favors healing of dry wounds. The in vivo efficacy of the formulations, evaluated in the modified diabetic male mice (db/db mice), showed that Carbopol alone was unable to induce improved healing and caused adverse reactions in some wounds. The inclusion of βG increased the epithelialization and wound contraction in the db/db mice when given at high βG:Carbopol ratio. The positive effect of βG was, however, not sufficient to counteract the adverse effect of Carbopol, thus a more suitable thickening agent should be investigated for further development of a sprayable wound care product.