Formulation and characterisation of alginate hydrocolloid film dressing loaded with gallic acid for potential chronic wound healing

Abstract

Background: A dramatic growth in the prevalence of chronic wounds due to diabetes has represented serious global health care and economic issues. Hence, there is an imperative need to develop an effective and affordable wound dressing for chronic wounds. Recent research has featured the potential of bioactive compound gallic acid (GA) in the context of wound recovery due to their safety and comparatively low cost. However, there is a scarcity of research that focuses on formulating GA into a stable and functional hydrocolloid film dressing. Thus, this present study aimed to formulate and characterise GA-loaded alginate-based hydrocolloid film dressing which is potentially used as low to medium suppurating chronic wound treatment. Methods: The hydrocolloid composite films were pre-formulated by blending sodium alginate (SA) with different combinations of polymers. The hydrocolloid films were developed using solvent-casting method and the most satisfactory film formulation was further incorporated with various GA concentrations (0.1%, 0.5% and 1%). The drug-loaded films were then characterised for their physicochemical properties to assess their potential use as drug delivery systems for chronic wound treatment. Results: In the pre-formulation studies, sodium alginate-pectin (SA-PC) based hydrocolloid film was found to be the most satisfactory, for being homogenous and retaining smoothness on surface along with satisfactory film flexibility. The SA-PC film was chosen for further loading with GA in 0.1%, 0.5% and 1%. The characterisation studies revealed that all GA-loaded films possess superior wound dressing properties of acidic pH range (3.97-4.04), moderate viscosity (1600 mPa-s-3198 mPa-s), optimal moisture vapor transmission rate (1195 g/m ²/day, 1237g/m ^2/day and 1112 g/m ²/day), slower moisture absorption and film expansion rate and no chemical interaction between the GA and polymers under FTIR analysis. Conclusion: An SA-PC hydrocolloid film incorporated with gallic acid as a potentially applicable wound dressing for low to medium suppurating chronic wounds was successfully developed.

Keywords: Alginate; gallic acid; hydrocolloid film; pectin; wound dressing.

Figure 1.

Macroscopic and microscopic images of (A) SA, PC and blank SA-PC hydrocolloid films and (B) Gallic acid-loaded films of various strengths (SA-PC-GA 0.1%, 0.5% and 1.0% w/v) taken on physical examination and under brightfield microscope at 4× magnification.

Figure 2.. FTIR spectra of (A) Blank SA-PC film, (B) Gallic acid-loaded film (SA-PC-GA 1.0%).

* Abbreviations: SA, sodium alginate; PC, pectin; GA, gallic acid.

Figure 3.. (A) Moisture vapor transmission rate (MVTR), (B) Moisture absorption % and (C) Expansion ratio (%) of film formulations incorporated with gallic acid (mean ± SD, n = 3).