CONICET | Buscador de Institutos y Recursos Humanos

Nanocapsules acting as drug carrier systems are widely used in the farmaceutical industry. When administered through the nasal mucosa, they may protect the drug from enzymatic degradation, increase the drug dissolution rate and act as a controlled release system resulting in prolonged blood concentrations. In this work, the encapsulating material of choice was chitosan (CS), which is a biodegradable, biocompatible and non-toxic amino polysaccharide derived from chitin. It has been extensively employed for developing drug delivery systems due to its excellent mucoadhesive properties. Insulin is one of the most used peptide drugs worldwide, for insulin-dependent patients treatments. The aim of our work was to determine the most efficient conditions to enable the nanoencapsulation of Insulin, under the molecular "self-assembly? concept. Insulin solution, 0.2 %, w/w, was kindly donated by Denver Farma Laboratories, Buenos Aires, Argentina. Chitosan was kindly donated by the Microbiology Laboratory of INTI Mar del Plata, Argentina. Particle size distribution and ζ-potential measurements were registered by dynamic light scattering (Zetasizer Nano-Zs, Malvern Instruments, Worcestershire, UK). Measurements were made at pH of 6 to favor electrostatic interactions between the two species.Variations in the ζ-potential values of Insulin-CS mixtures were observed upon increasing concentrations of CS. The CS mass needed for insulin charge titration was 10-3 % w/w; this result would indicate the appropriate biopolymers mass ratio to ensure generation of core-shell nanocapsules. Thus, Insulin-CS mixtures particle size distribution was obtained for several CS concentrations, exhibiting a noticeable shift from free insulin size distribution. Additionally, CS may induce molecular changes in protein structure as determined by fluorescence spectroscopy at pH of 6.Finally, the nanocapsules's structure and topography were characterized by SEM.

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