Chitosan gel containing polymeric nanocapsules: a new formulation for vaginal drug delivery.

The vaginal route of administration is an alternative for several treatments for either local or systemic pharmacological effects. However, the permanence of a drug in this route represents a challenge for formulation development that can be overcome by using nanoencapsulation and chitosan gel. Thus, this work aimed to evaluate the performance of chitosan hydrogels containing cationic and anionic acrylic-based nanocapsules (Eudragit RS 100 and Eudragit S 100, respectively) with Nile red as a model of lipophilic substance in the vaginal route of administration, as measured by increases in the residence time and the penetration of these formulations. Several formulations were prepared with increasing chitosan concentrations, and were analyzed in terms of pH and rheological behavior so that the most suitable formulation could be selected. The enhancement of the adhesion (tensile stress test and washability profile) and penetration (confocal laser scanning microscopy and extraction followed by quantification) properties of the formulations, when applied to porcine vaginal mucosa, were evaluated. The nanocapsule suspensions produced presented adequate properties: size of approximately 200 nm (polydispersity index of ≤0.2); zeta potential around +10 mV for the cationic formulation and -10 mV for the anionic formulation; and pH values of 6.1±0.1 (Eudragit RS 100), 5.3±0.2 (Eudragit S 100), 6.2±0.1 (Nile red loaded Eudragit RS 100), and 5.1±0.1 (Nile red loaded Eudragit S 100). The chitosan formulation presented suitable viscosity for vaginal application and acidic pH (approximately 4.5). The tensile stress test showed that both formulations containing polymeric nanocapsules presented higher mucoadhesion when compared with the formulation without nanocapsules. In the washability experiment, no significant differences were found between formulations. Confocal microscopy and fluorescence quantification after extraction from the mucosa showed higher penetration of Nile red when it was nanoencapsulated, particularly in cationic nanocapsules. The formulations developed based on chitosan gel vehicle at 2.5% weight/weight containing polymeric nanocapsules, especially the cationic nanocapsules, demonstrated applicability for the vaginal delivery of hydrophobic substances.

Preparation and characterization of polysaccharide-based nanoparticles with anticoagulant activity.

The aim of this study was to produce and characterize nanoparticles (NPs), combining chondroitin sulfate (CS) and fucoidan (FC) with chitosan for therapeutic purposes. These NPs were characterized by dynamic light scattering, zeta potential determination, and transmission electronic microscopy. The anticoagulant activity was determined for FC NPs and compared with FC solution at the same concentration. FC NPs showed regular shapes and better anticoagulant activity than free polysaccharide solution. FC solution did not affect coagulation compared to FC NPs, which increased up to two-fold, even at a lower concentration. Cytotoxicity and permeability tests were conducted using Caco-2 cell monolayer, exhibiting no toxic effect in this cell line and higher permeability for NP2 samples than FC solution at the same concentration.