Preparing, characterizing, and evaluating chitosan/fucoidan nanoparticles as oral delivery carriers

In designing an effective oral delivery system, the harshness of the gastrointestinal tract is a key limitation. Therefore, developing a pH-responsive carrier is crucial. We designed a chitosan/fucoidan nanoparticle (CS/F NP) and evaluated its potential as an oral delivery carrier. The results indicate that the CS/F NPs were successfully prepared based on their electrostatic interactions. They were approximately 380 nm, revealing significant pH-sensitive properties as the weight ratio of CS to F was 1:1. The isoelectric point of the CS/F NPs was 5.7. Using gamma scintigraphy, the 99m Tc-methylene diphosphonate encapsulated CS/F NPs were quite stable at pH 2.5 and decomposed at pH 7.4. For long-term storage, trehalose (20 %, w/v) is a suitable cryoprotectant. The outcome of the transepithelial electric resistance (TEER) of the Caco-2 monolayer shows that CS/F NPs effectively enhanced the opening of the cell tight junction. Briefly, the CS/F NPs developed are promising carriers for an oral delivery system.