FORMATION OF NANOPARTICLES BASED ON ELECTROSTATIC COMPLEXATION WITHIN MICROCHANNELS AIMING VEICULATION OF ACTIVE COMPOUNDS.

Absorption efficiency of bioactive compounds can be increased if they are incorporated in nanoparticles mainly due to the increased surface area allowing transference improvement. These systems can be obtained by several techniques but electrostatic complexation comes up as an interesting path. To perform this methodology at least two oppositely charged polymers are used triggering complex formation by their interaction through electrostatic intermolecular forces. For instance, electrostatic complexes may be formed by combining chitosan and gellan gum. Chitosan possesses interesting features such as intestinal mucoadhesiveness, while gellan gum shows resistance to low pH values. Therefore, we aimed to evaluate the formation of nanoparticles based on electrostatic complexes using gellan gum (G) combined with hydrolyzed chitosan (H) focusing on their use as vehicles for bioactive compounds. To obtain the nanocomplexes, polysaccharides were mixed at the concentration of 0.01% w/v and pH 4.5 using both bulk and microfluidic methods. Afterwards, the systems were characterized by zeta potential measurements, particle size distribution and polydispersity (PDI). G and C solutions presented Newtonian behavior and showed zeta potential of -32.4 mV and +45.03 mV, respectively. Particle size values of obtained complexes (G:C) using the bulk method and G:C ratio of 8:2 and 7:3 were between 100 and 1000 nm whilst PDI values ranged from 0.214 to 0.327. Moreover, zeta potential values were of -10.4 mV and 17.1 mV, respectively. Interestingly, complexes obtained by the microfluidic technique in the same aforementioned conditions presented a smaller size, ranging from 100 to 400 nm with a PDI between 0.09 and 0.11. Zeta potential values were similar to those found for the bulk technique (-12.1 mV and 16.8 mV, respectively). Thus, we can conclude that microfluidic devices provided better efficiency -lower values of both PDI and particle size- revealing the great potential for future studies of encapsulation using complexation-based systems.