Insulin-chitosan nanocomplexes design for hormone controlled delivery

CECILIA PRUDKIN SILVA; OSCAR E. PÉREZ; FEDERICO COLUCCIO LESKOW; KARINA D. MARTINEZ

La Plata

Workshop; Imaging Techniques for Biotechnology and Biomedical Applications; 2016

p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left; }p.western { font-family: "Times New Roman",serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman"; font-size: 10pt; }p.ctl { font-family: "Times New Roman"; font-size: 10pt; }a:link { color: rgb(0, 0, 255); }Nanoencapsulation can protect a ligand fromharsh environments, make it target-specific, increase itsbiodisponibility and control its release profile, therefore,nanocapsules are widely used in the farmaceutical industry as drugcarrier systems.In this work, the encapsulating material ofchoice was chitosan (CS), a kind gift bythe Microbiology Laboratory of INTI Mar del Plata, Argentina.Chitosan is a non-toxic, biocompatibleand biodegradable biopolymer, with mucoadhesive andabsorption-enhancing properties and it has been extensivelyemployed for developing drug delivery systems. Insulin,one of the most used peptide drugs worldwide, waskindly donated by Denver Farma Laboratories, Buenos Aires, Argentina.Its concentration was kept constant at 0.2 %, w/w throughoutthe experiments.The aim of our work was to determine the most efficient conditionsto enable the nanoencapsulation of Insulin, under the molecular"self-assembly? concept. Particle sizedistribution and ζ-potentialmeasurements were registered by dynamic light scattering (ZetasizerNano-Zs, Malvern Instruments, Worcestershire, UK).Measurements were made at pH of 6 to favor electrostatic interactionsbetween the two species.Variations in the ζ-potentialvalues of Insulin-CS mixtures were observed upon increasingconcentrations of CS. The CS mass needed for insulin charge titrationwas 10-3 %w/w; this result would indicate the appropriate biopolymers massratio to ensure generation of core-shell nanocapsules. Thus,Insulin-CS mixtures particle sizedistribution was obtained for several CS concentrations,exhibiting a noticeable shift from free insulin size distribution.Additionally, CS may induce molecular changes in protein structure asdetermined by fluorescence spectroscopy at pHof 6.Finally, the nanocapsules's structure andtopography were characterized by SEM.