Performance Assessment of Chitosan-Surfactin Nanocomplex for pH-stimulated Potential Oral Delivery of Curcumin

Contemporary R&D activities aimed at enhancing the delivery of insoluble food bioactives have focused on the development of sustainable nanomaterials. In this study, a novel self-assembled complex of cationic biopolymer chitosan (CS) and anionic biosurfactant surfactin (SF) was successfully developed via the nanoprecipitation method for the encapsulation of bioactive curcumin (Cur). Complex formation is driven by a synergistic interplay of electrostatic and hydrophobic interactions as revealed by comprehensive physicochemical and thermodynamic investigation. An amorphous form of Cur was loaded in the CS-SF nanocomplex, as evidenced from X-ray diffraction pattern and differential scanning calorimetry. The CS-SF-Cur nanocomplex exhibited spherical core-shell morphology as revealed by FESEM and TEM imaging with a hydrodynamic diameter of 302.37 ± 51.98 nm and a polydispersity index of 0.34 ± 0.1. The encapsulation and loading efficiencies of Cur were 86.1 ± 0.21% and 45.48 ± 1.9%, respectively. The Cur-loaded nanocomplex performed better than the CS-SF nanocomplex with respect to its storage stability, thermal stability, and water solubility. In vitro drug release was significantly higher (67.58 ± 2.5%) at physiological pH as compared to the same at an acidic pH (27.53 ± 1.16%) following the Hixson-Crowell release model, which is governed by polymer erosion and non-Fickian diffusion mechanisms. Under simulated gastrointestinal conditions, the nanocomplex presented moderate stability and improved Cur bioacessibility (57.14 ± 2.7%) in the intestinal phase. The nanocomplex demonstrated hemocompatibility and statistically higher antioxidant properties (75 ± 1.97%) in comparison to free Cur. Overall, the biopolymer-biosurfactant complex (BBC) offers a new sustainable nanoplatform for a potentially stable and effective oral delivery system for poorly soluble bioactives.