Highly thiolated corn starch for enhanced mucoadhesion and permeation

Area of Science:

• Materials Science
• Pharmaceutical Sciences
• Biotechnology

Background:

• Developing novel excipients is crucial for effective mucosal drug delivery.
• Corn starch is an abundant and biocompatible polysaccharide.
• Thiolation can modify starch properties for enhanced functionality.

Purpose of the Study:

• To synthesize and characterize highly thiolated corn starch.
• To evaluate its mucoadhesive and permeation enhancing properties.
• To assess its potential as an excipient for mucosal drug delivery.

Main Methods:

• Chemical thiolation of native corn starch using phosphorous pentasulfide.
• Characterization using Ellman's test, 1H NMR, FTIR, and DSC.
• Cytotoxicity assessment via resazurin viability assay.
• Evaluation of swelling, viscosity, mucoadhesion (rheology, tensile testing), and permeation (using sodium fluorescein).

Main Results:

• Thiolated starch (1658 μmol/g thiol groups) exhibited no cytotoxicity at 0.2 mg/ml.
• A 3.5-fold increase in dynamic viscosity and a 91.1-fold enhancement in mucoadhesion were observed.
• Tensile testing showed a 4.3-fold increase in detachment force.
• A 2-fold increase in permeation enhancement of sodium fluorescein across rat intestinal mucosa was demonstrated.

Conclusions:

• Highly thiolated corn starch possesses significant mucoadhesive and permeation enhancing capabilities.
• The modified starch demonstrates good safety profile.
• It represents a promising excipient for advancing mucosal drug delivery systems.