Optimization of a mucoadhesion testing protocol using a vertical force measurement system for chitosan- and...

The aim of this study was to optimize a mucoadhesion testing protocol utilizing a vertical motorized test stand combined with a digital force gauge. The optimized protocol was applied to evaluate the mucoadhesive performance of various test materials, including lyophilized polymer matrices composed of chitosan, pectin, poly(vinyl alcohol) (PVA), and hydroxypropyl methylcellulose (HPMC); compressed pectin-only disks; and commercial enteric-coated (HPMC-based) capsules.

Optimization involved systematic evaluation of key test parameters including start speed, applied contact force, contact time, and return (detachment) speed. Standardized simulated gastric (SGF, pH 2) and intestinal fluids (SIF, pH 6.8) containing 1 % w/v mucin were employed as test media. Final measurements were expressed as detachment force normalized to the contact area (N/cm²) and corrected for baseline adhesion in mucin-free media.

Optimized conditions (start speed 10 mm/min, force 1 N, contact time 60 s, return speed 60 mm/min) allowed sensitive detection of material differences. Pressed pectin discs showed the highest mucoadhesive strength (>20 N/cm²).

The developed method is reliable for evaluating mucoadhesion using mucin-containing media. Polymer composition, environmental pH, and lyophilization strongly influenced adhesive performance. The protocol offers a standardized tool for the design of mucoadhesive drug delivery systems.