Chitosan and Chitosan Nanoparticles Applications in Oral Drug Delivery

Currently, one of the most common ways to use the drug is to take it orally. It is easier and less painful than other common methods, such as intravenous or intramuscular injections. However, the effectiveness of drugs in these conditions is very limited due to poor pharmacokinetic behaviors and the sensitive structures of the drug molecules. Therefore, drugs need to be protected along the way to reach the drug delivery destination. It is important to design nanocarriers that are resistant to the acidic fluid of the stomach while changes in the intestinal fluid due to the environment of the gastrointestinal tract, such as the significant difference in the pH of the gastric and intestines.
Chitosan (CS), a cationic polysaccharide, has received widespread attention due to its inherent mucosal adhesion properties, modulation of epithelial tight junction integrity, biocompatibility, biodegradability, improved stability, low toxicity, simple and gentle preparation methods, and various drug delivery solutions. Chitosan nanoparticles are prepared and characterized by different techniques. In addition, chitosan derivatives such as thiolated and carboxylated chitosan have been investigated to increase the effectiveness of oral drug absorption, effective dose control, and reduced side effects.
Moreover, the synthesis of chitosan nanoparticles, different synthesis methods, their widespread applications as oral drug delivery carriers, and their effects on drug delivery were investigated. This study aims to further development of these nanoparticles as effective therapeutic and diagnostic carriers in the future.