Biophysical characterization of inulin encapsulated insulin in simulated gastrointestinal fluid Achmad Ramadhannail Rasjava, Rukman Hertadi*
Department of Chemistry, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
*rhertadi[at]itb.ac.id
Abstract
Development of biopolymer-based nanocarriers for oral insulin delivery has gained significant attention in recent years due to the challenges posed by insulin instability against gastric acid. This study evaluates the effectiveness of inulin produced by the halophilic bacterium Salinivibrio sp. GM01 as an insulin carrier. The synthesis of inulin-encapsulated insulin is optimized using the response surface method. The optimized conditions yielded a high entrapment efficiency of 87% by employing 53 mg of inulin, stirred at 17,800 rpm for 10 minutes. The resulting spherical nanoparticles exhibited an average diameter of approximately 511 nm. The efficacy of inulin as an insulin nanocarrier was assessed through encapsulation stability and conformational protection studies using simulated gastric and small intestinal fluids. Encapsulation stability remained consistent across both fluids, with inulin demonstrating resistance to pH variations. Circular dichroism and spectrofluorescence analysis revealed conformational stability differences between encapsulated and free insulin in gastric simulated fluid. Insulin encapsulation by inulin was shown to enhance the protection of insulin conformation by increasing the activation barrier for denaturation at the secondary and tertiary levels by 0.28 kcal/mole and 1.53 kcal/mole, respectively. These results highlight the potential of inulin as a promising material for the development of oral insulin delivery systems. The utilization of inulin-based nanocarriers offers a viable approach to address the challenges associated with insulin instability, thus paving the way for enhanced therapeutic outcomes in oral insulin delivery.
