Development of Bromelain-Loaded Chitosan/Alginate Bilayer Film for The Wound Dressing Applications

Abstract

Wound healing is a naturally occurring process in our body and comprises various phases like hemostasis, inflammation, proliferation and remodeling. Bromelain, a natural cysteine protease, is a multifunctional molecule with analgesic and anti-inflammatory effects that aid in the treatment of wounds. This study focuses on developing chitosan/alginate bilayer film by incorporating bromelain (0,0.5,1,1.5 and 2% w/v) in the alginate layer via layer-by-layer assembly. Bilayer films were prepared by solvent casting method and were systematically characterized physicochemically, mechanically and biologically in in-vitro. Scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopic analysis determined the surface morphology and functional groups of bromelain in the alginate layer. Further, the swelling (%), tensile strength, wettability and moisture transmission rate of films was also determined. In-vitro drug release (pH 7.4) and its kinetics were studied to determine the bromelain release and its mechanism using Korsmeyer-Peppas, Higuchi, Zero-order and Peppas-Sahlin models. Hemolysis assay and cell viability assay in in-vitro were performed to assess the hemocompatibility, toxicity of films. The surface morphology from SEM revealed that bromelain was homogeneously dispersed and disruption of alginate bonds by bromelain was studied in FTIR analysis. The high mechanical strength (60.05±2.45 MPa for 0.5 % w/v of bromelain) of the bilayer films decreased with an increase in the concentration of bromelain. The bi-layered films possessed an excellent swelling rate of around 300 - 350% and tend to be slightly hydrophobic (61.71±1.68 to 72.51±3.11° for the alginate layer and 89.84±3.29° for the chitosan layer) due to the bromelain interaction, which reduced the free hydroxyl groups in the alginate layer. The moisture transmission rate decreased with an increase in the concentration of bromelain. The drug release depicted that 2% w/v of bromelain showed an initial burst release, while other concentrations showed a slower release rate. From the drug release kinetics, the Korsmeyer-Peppas model was found to be the closest fit. Bilayer films depicted good hemocompatibility and cell viability above 80%. The study demonstrated that bilayer film incorporated with bromelain (up to 1.5% w/v) might be a potential drug-delivery system for wound dressing applications.