Unlocking the potential: Bacterial exopolysaccharide as a smart drug-delivery vehicle for controlled in vitro drug release

Abstract

Conventional methods of drug administration often face limitations such as poor bioavailability, rapid clearance, and undesirable side effects. To overcome these, microbial exopolysaccharides (EPS) have emerged as promising biomaterials due to their ability to serve as biocompatible, biodegradable, and efficient drug carriers. This study focuses on the potential of an EPS extracted from Bacillus sp. EPS003 to function as a novel carrier system. Quercetin, a bioactive flavonoid with therapeutic significance, is chosen as the model drug to develop EPS-based quercetin-loaded microparticles (MPs). The MPs have been structurally characterized using UV-visible and FTIR spectroscopy, while particle size and zeta potential measurements confirmed their uniformity and stability. Thermal properties are analyzed by thermogravimetric analysis (TGA), and surface morphology with elemental composition is examined through SEM-EDAX. Drug loading efficiency and capacity are quantified, and in vitro release kinetics is studied. The results revealed that quercetin release followed a zero-order kinetic model with a high R² value, suggesting diffusion-controlled release. The biofunctional properties of the MPs are also assessed. Antioxidant potential is determined using the DPPH radical scavenging assay, while the anti-inflammatory property is evaluated via egg albumin denaturation. Notably, the quercetin-loaded EPS demonstrated 94.6% anti-inflammatory activity, with enhanced antioxidant and anti-inflammatory effects compared to quercetin or EPS alone. Overall, the findings indicate that EPS from Bacillus sp. EPS003 can serve as an excellent drug-delivery vehicle, ensuring controlled release without compromising drug stability or activity, thus offering a novel strategy for therapeutic applications.