Nanoencapsulation of Bioactive Compounds

A protein is composed of more than 50 amino acids (>5000 Da) in the form of a long chain, while peptides consist of a smaller group of less than 50 amino acids (500–5000 Da) linked by peptide bonds. They play various essential roles in the body, including transporting molecules, catalyzing chemical reactions, and responding to stimuli. These molecules are highly susceptible to extreme pH levels and enzymatic degradation, particularly by proteolytic enzymes in the gastrointestinal tract, which break the peptide linkage in proteins and peptides. Additionally, due to their higher molecular weight, proteins cannot effectively cross the intestinal membrane. As a result, extensive research has focused on the oral delivery of these molecules, employing techniques such as chemical modification, PEGylation, peptidomimetics, absorption enhancers, and membrane transporters, often in conjunction with nanoparticle-based delivery systems. Notably, chitosan and solid lipid nanoparticles have been identified as promising nano-carriers for peptide encapsulation (Das et al. 2019). Insulin was encapsulated using cetyl palmitate-based solid lipid nanoparticles, which resulted in a hypoglycemic effect in diabetic rats after 24 h, demonstrating enhanced oral absorption of insulin. Similarly, Reboredo et al. (2021) used zein nano-particles coated with poly(anhydride)-thiamine conjugate to encapsulate insulin-loaded nano-particles, reducing blood glucose levels in rats by up to 20% (Table 7.1).