Structure of Chitosan Determines Its Interactions with Mucin

• Published in: Biomacromolecules 2014-10, Vol.15 (10), p.3550-3558
• Main Authors: Menchicchi, B, Fuenzalida, J. P, Bobbili, Kishore Babu, Hensel, A, Swamy, Musti J, Goycoolea, F. M
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Applied sciences; Biological and medical sciences; Chemistry, Pharmaceutical - methods; Chitosan - chemistry; Chitosan - metabolism; Drug Delivery Systems - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gastric Mucins - metabolism; General pharmacology; Glycoproteins; Helicobacter pylori; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Medical sciences; Mucins - chemistry; Mucins - metabolism; Nanostructures - chemistry; Natural polymers; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Physicochemistry of polymers; Proteins; Starch and polysaccharides; Static Electricity; Swine
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm5007954

Synthetic and natural mucoadhesive biomaterials in optimized galenical formulations are potentially useful for the transmucosal delivery of active ingredients to improve their localized and prolonged effects. Chitosans (CS) have potent mucoadhesive characteristics, but the exact mechanisms underpinning such interactions at the molecular level and the role of the specific structural properties of CS remain elusive. In the present study we used a combination of microviscosimetry, zeta potential analysis, isothermal titration calorimetry (ITC) and fluorescence quenching to confirm that the soluble fraction of porcine stomach mucin interacts with CS in water or 0.1 M NaCl (at c < c*; relative viscosity, ηrel, ∼ 2.0 at pH 4.5 and 37 °C) via a heterotypic stoichiometric process significantly influenced by the degree of CS acetylation (DA). We propose that CS–mucin interactions are driven predominantly by electrostatic binding, supported by other forces (e.g., hydrogen bonds and hydrophobic association) and that the DA influences the overall conformation of CS and thus the nature of the resulting complexes. Although the conditions used in this model system are simpler than the typical in vivo environment, the resulting knowledge will enable the rational design of CS-based nanostructured materials for specific transmucosal drug delivery (e.g., for Helicobacter pylori stomach therapy).