Triborheological Analysis of Reconstituted Gastrointestinal Mucus/Chitosan:TPP Nanoparticles System to Study Mucoadhesion Phenomenon under Different pH Conditions.

ABSTRACT

Polymeric nanoparticles have attracted much attention as pharmaceutical delivery vehicles to prolong residence time and enhance the bioavailability of therapeutic molecules through the mucoadhesive phenomenon. In this study, chitosanTPP nanoparticles were synthetized using the ionic gelation technique to analyze their mucoadhesive interaction with reconstituted porcine gastrointestinal mucus from a triborheological point of view under different pH conditions (pH = 2.0, 4.0, 6.0 and 7.0). The triborheological profile of the reconstituted mucus was evaluated at different pH environments through the oscillation frequency and the flow sweep tests, demonstrating that the reconstituted mucus exhibits shear thinning behavior regardless of pH, while its viscoelastic properties showed a change in behavior from a polymeric solution performance under neutral pH conditions to a viscoelastic gel under acidic conditions. Additionally, a rheological synergism analysis was performed to visualize the changes that occur in the viscoelastic properties, the viscosity and the coefficient of friction of the reconstituted mucus samples as a consequence of the interaction with the chitosanTPP nanoparticles to determine or to discard the presence of the mucoadhesion phenomenon under the different pH values. Mucoadhesiveness evaluation revealed that chitosanTPP exhibited strong mucoadhesion under highly acidic pH conditions, below its pKa value of 6.5. In contrast, at neutral conditions or close to its pKa value, the chitosanTPP nanoparticles' mucoadhesiveness was negligible.