Stabilization of insulin using low molecular weight chitosan carbonate nanocarrier.

The current study aims to design a nanoparticulate system that could encapsulate insulin and improve its stability. Nanoparticles were formulated by ionic cross-linking of chitosan (CS) with carbonate divalent anions. The interaction between the two moieties was evidenced by AFM, FTIR and surface tension measurements. CS carbonate nanoparticles were prepared with different mole fractions. The mole fraction of carbonate that produced the smallest size nanoparticles and highest zeta potential (40 nm and +39 mV, respectively) was determined. Circular dichroism (CD) studies revealed that insulin conformation was not affected by CS at 20 °C. However, the studies at elevated temperatures demonstrated that CS had a role in insulin stabilization. Fluorescence spectroscopy indicated the interaction between insulin and CS carbonate. The findings from this investigation showed the potential use of CS carbonate as an insulin stabilizer and at the same time as an insulin nanocarrier system.